I was 47, shaking and with tears streaming down my face as I held a perfect baby girl in my arms. My body was zinging with oxytocin, the bonding hormone, in response to her smell and touch, those little breaths – it felt as if she was my newborn baby. She wasn’t. She was my first grandchild. My daughter’s daughter. I’d become a mum at 21, she was 26…

The following evening, for my best friend’s landmark birthday, I had made an effort –hair done, party frock, high heels – and I stepped confidently into the room. The first person I saw shouted: “Hi Grandma!”

I had to stop myself from slapping him. I was totally up for the love of this new being in my life, but I was by no means ready for the new status of grandmother.

It forced me to re-evaluate how I saw myself; how to reconfigure my relationship with my daughter to allow her the space to be the mother she needed to be – and work out what kind of grandmother I was. And, of course, there were my issues around ageing. I’d seen other phases of my life as a development, but for me being a grandmother brought up images of grey-haired old women on the slippery slope to death. I wanted to avoid it – anti-ageing being the operative word. But I couldn’t. I had to face the discomfort, the siren call of change, and do the work of change.

I needed the courage and endurance to actively adapt, allowing the pull and push of expanding to love anew while facing the challenge of letting go. It meant I had to let the anxious feelings run through my body, rather than cut them off with busyness, which is my most common defence. I often think of it like the weather: I needed to let the storm run through my system, while supporting myself by a process of talking, crying and running to reduce the stressors charging around my body. Then choosing to do things that comforted me: cosy TV viewing, hugs, meditation, delicious food.

My experience felt unique and somehow unfamiliar, but research shows that change – either through choice, external events or developmentally – occurs every seven to 10 years. Yes the seven-year itch is true. It is important to set it in the context that there has been more societal change in the past 50 years than ever before. Boundaries are more fluid in work, love, health, sexuality, gender, identity and religion. I couldn’t look at my mother and see her as a road map of how I wanted to be as a grandmother. I had more choices, which should have been exciting, but actually felt overwhelming. Life is change, I know it, and yet my experience, as it is for others, was trickier than I expected, and I assumed I must be doing it wrong.

I have been a psychotherapist for 30 years and every person who has walked through my door has had a problematic relationship with change. It could be that they hated not having control over the circumstances that had been forced on them, or they were furious with their emotional self for not catching up and chiming with their new job, role or status. Confusion triggered by anxiety was their first response: the external event was easy to describe, but making sense of how they felt was not.

When we try and resist change we have worse outcomes

They usually blocked the pain by shutting down, but when they blocked one end of their emotional spectrum, they also blocked the other – their capacity to feel joy. They had to open themselves up to their full experience and recognise they couldn’t fix it or will it to be different. Our work was to examine their conflicting thoughts, support them to express their feelings, bring to the surface what might be hidden and help them come to accept it – until there came a moment when they realised they had integrated the change.

The process requires patience and commitment – it can take up to a year, or more. Whether the changes feel like success or failure, the key is to learn from them – for that is how we expand and grow through our life. When we resist change we have worse outcomes. The evidence is unequivocal. Those who resist change suffer more when change is forced on them – and have less joy and less success in life.

At the heart of change is identity. When someone asks themselves who am I, it is through identity that they find their answers. A cohesive sense of identity is fundamental to our mental health, and if there is a clash with who we know we are and who we think we should be, we suffer.

One of my clients, Owen, was struggling with his identity. He was 22 and had been having a difficult time since coming out at university. He’d begun to question everything and started to feel uneasy and awkward around people who had previously been his bedrock.

“When I came out,” he told me, “that pretty much changed my entire life. Not necessarily for the better. Of course for the better in the round, but my comfort blanket, my confidence, my sense of belonging, were flicked away.”

It became clear that two parts of him clashed: the conventional part, which wanted to belong to the majority, and the gay part, which in some ways liked being different, but didn’t know how to live fully in its gay self. The two parts didn’t converse. As he talked to me he was talking to himself. He began to see where the source of his pain was. He realised that at the heart of identity is the need to love and belong, and for that he needed to allow this emerging identity to thrive.

Another client, Cindy, lost her job and found that she had never examined her beliefs about herself, saying: “I’m a loser.” She went on a roller coaster of anxiety, as most people who face change do. Anxiety is a form of energy that forces us to adjust, informing us we have to shift our role, behaviour or view. We need to shed the old way of being, like reptiles shed their skin, for a new way to grow.

The more we are able to adapt, the richer our life is likely to be

Cindy did not sabotage the change that was required. Her underlying attitude was that of a survivor: hope kept her afloat, picked her up when she crashed. Hope is key to moving forward. Hope is a feeling, but it is also about how we think. Our need to set realistic goals, work out how to achieve them, including the adaptability for a backup plan, and finally self-belief.

Finding love, losing love or being unhappily in love is a constant theme in my practice. Maria was a case in point. She came to see me because she was at a crossroads in her life: she was in her mid-50s, had been married for 26 years, had three daughters, and there were fundamental questions about love and marriage that she needed to answer. Through her two lovers Maria had discovered aspects of herself that felt entirely new: each man had opened up a different version of her that had been hidden through the faithful years of her marriage to Ken.

It was fascinating exploring her question: “How come I have the capacity for another lover? What is my unmet need?” By the time we found answers to those questions, Maria told me: “I’ve folded a lot of my past pain into my heart.” We never lose where or who we’ve been, which can be a source of potency and growth.

It is surprising how transformative talking to a therapist for only an hour a week can be. But I began to see that everything my clients chose to do or not do had an impact on their wellbeing. For that reason I developed the “Eight Pillars of Strength” – a concrete guide to the actual things we can do to help us when we are overwhelmed and immobilised by present feelings, or focused on an imagined future we dread or long for.

Each pillar outlines the attitudes, ways of being and the good habits that help build our robustness. It covers our relationship with our self and with others, how to manage our emotions, outlines an exercise regime, shows how structure can support us, details our relationship with time, the importance of limits and boundaries, and describes a brilliant technique to both calm oneself and access the wisdom of the body.

The fact is that the more we are able to adapt, the richer our life is likely to be; unresolved issues from the past lead to more difficult transitions in later life. If there is one abiding truth that came through all my research, client work and thinking from writing this book, it was that when we look back at our lives it is our love and connection to others that matters to us most.

This Too Shall Pass: Stories of Change, Crisis and Hopeful Beginnings by Julia Samuel is published by Penguin Life on 5 March at £14.99. Buy a copy for £12.59 from guardianbookshop.com