Twelve months ago Shariff Xamza was celebrating at a Ramadan dinner for a long-lost friend visiting from the US. They hadn’t seen each other since the early 90s when civil war broke out in Somalia, and spent the balmy June evening catching up in a restaurant in Finsbury Park in north London. “It was a good time, we broke our fast together, chat chat chat, with lots of us coming to see him,” Xamza remembers.

The group wanted to go on to a nearby Ethiopian coffee house but there was work the next day so Xamza (pronounced “hum-za”) left before midnight and headed down the road to his parked car. In the next few moments, outside Finsbury Park’s Muslim Welfare Centre, a white van ploughed into the pavement. The perpetrator shouted that he wanted to “kill all Muslims”. Xamza was hit and lost consciousness, bleeding heavily.

“I remember seeing a big crowd to my left,” he says, “and usually I don’t head to a crowd because I am a close protection officer and we are trained to stay back and assess the situation. Then I heard people say, ‘Clear the way, clear the path, he needs to breathe’, and I realised I needed to be there to give first aid. Someone shouted me: ‘Hey Shariff! Come help!’”

Makram Ali, a 51-year-old with six children, had left the mosque after tarawih prayers and collapsed on the street when Xamza arrived. “I was leaning down to give him first aid,” Xamza remembers, “then next thing, I wake up and I’m lying down in hospital and everyone is shaking my hand.”

Darren Osborne, apparently radicalised online in his hatred of Muslims and by watching the BBC drama about sexual abuse in Rochdale, Three Girls, hired a van in Cardiff to drive to London to commit terrorism. Nine people, including Xamza, were seriously injured by his attack on 19 June last year, and Ali died at the scene. In February, Osborne, 47, was found guilty at Woolwich crown court of murder and attempted murder and jailed for life with a minimum of 43 years.

“I don’t think about him, I didn’t see him, I only saw him during the court,” says Xamza. “His motive? I have no idea the reason he did it, I don’t think all British think this way or do this way. The reason he did it, I have no idea. But to be honest, he ruined our lives. Everything is disrupted and changed, it has impacted everything. My family, my job, my social life.”

Xamza, 49, who is of Somali-Arab heritage, is married with four children and has lived in the UK for more than 20 years. He sits upright, smart and proud, in the living room in the family’s 15th-floor flat in east London. He is in “a lot of pain all the time”, but is determined to “get back to what I had before, who I was before”. Working as a close protection officer – that is to say, bodyguard – with years of experience and qualifications, Xamza made a career of protecting people. He speaks four languages (Somali, Dutch, Arabic and English) and his main gig was with a French security firm on a zero-hours contract.

Tributes to the victims of the attack. Photograph: Xinhua/Barcroft Images

“You earn what you work and unfortunately, there is nothing else they offer so my family have had a lot of hardship. I couldn’t pay rent, pay bills. My wife works part-time and my daughter as well but we have struggled,” he says. But the burden goes far beyond finances.

“Life is hard, it’s too much,” says Xamza of the past year. “I have anxiety, depression and flashbacks. I have violent sleep – wake up crying, kicking, punching. With my wife, we have had problems we didn’t have before and separated at times in these months. I have to stay with my mum sometimes. And my kids complain that I am angry and upset and changed. Before I would be out working, socialising, looking after my family. Now I am very limited and we have problems.”

Xamza was in and out of hospital in the first few weeks after the attack. He sustained a head injury, which is still causing him significant problems – blurred vision, mood swings, intense vertigo – and lost his hearing. His eyes swelled because of an allergy to medication and he was dispatched to Moorfields eye hospital for further treatment. He has lost feeling on the left side of his face and his shoulder is severely damaged; the collarbone has popped and is jarring out of his clavicle, for which he is having further surgery this week.

He spills open a bag full of medication: packets of antidepressants, painkillers, sleeping pills, plus medication for acid reflux, blood pressure, sprays for his eyes and nose, batteries for his hearing aid. A psychologist visits him once a month.

“She always helps me and is very kind,” he says, “without her I would be with so many problems mentally. Every day you think of new things: ‘Why did it happen?’ ‘Why don’t you do your job?’ ‘Will you ever be the same?’” The irony of working in a job designed to keep others safe and being caught up in a terrorist attack himself isn’t lost on Xamza but he is determined to get his life back.

“Before this happened to me, I was planning to go back to my country. I got the military rank to train the president’s guards and at the same time to be part of his security – this was my goal. When you are in security, you are responsible for everything – the building, the person – you have to be fit and sharp. But I was hopeless after this happened. I have 35 certificates of security, I am qualified and I want to go back, I just have to …” He waves at his shoulder and shakes his head.

There is a drudgery to the pain endured by Xamza and others like him, where a life of vitality and purpose has been reduced to whiling away the hours within four walls, afraid to go out and unfit to work.

His solicitor, Dushal Mehta of FieldFisher, who has represented victims of the Westminster, London Bridge and Finsbury Park terror attacks, punctures the assumption that help – financial and medical – falls into place after such radically life-changing events.

“With this particular incident, we have found that we have a very proud community who are very reluctant to come forward and ask for help when they so desperately need it but are so grateful for any support when they receive it,” he says. While the Muslim community in Finsbury Park rallied around and gave families between £1,000 and £4,000 in donations, victims have shunned the press. “Part of that is that they don’t want to be perceived as putting their head above the parapet,” says Mehta.

Xamza is visibly drained by the end of our conversation. “I have anxiety, depression, I get scared, but I am much better than before,” he says. “God sends you tests in good times and bad times. This is a test.”