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Marla Genova had resigned herself to a career in dry cleaning. The then-teenager couldn't imagine doing anything less isolating or mundane than what she did at that post-high school job: sitting at the dry cleaner's, mostly alone, until the one time each day the clothes were delivered. "Basically, I just sat there," says Genova, who's now 40 and lives in Bristol, Connecticut. "I could have seen myself sitting there forever." Genova may have looked apathetic, unambitious or even unintelligent, but what she really was was anxious. She didn't receive an official diagnosis – social anxiety disorder – until she was screened for anxiety during an awareness event at college, even though she'd always known something was wrong. Soon after the diagnosis, she enrolled in a social phobia group research study that taught cognitive behavioral therapy. There, Genova began trusting she could do a lot more with her life than sit. "[The CBT program] changed my entire way of thinking, and I was able to apply it to other parts of my life as well," says Genova, who spent 20 years conducting clinical research on anxiety disorders and other behavioral and public health issues before launching Socially Speaking, a social performance and anxiety coaching business. More from US News & World Report:

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How you can prepare for a child to leave home Anxiety – as it refers to a set of disorders including social anxiety disorder and generalized anxiety disorder, which Genova also has – affects more than 18 percent of the U.S. adult population each year, making it the most common mental illness in the country, according to the Anxiety and Depression Association of America. "Anxiety is definitely becoming more common. … Chances are, you know someone who suffers from it," says Angelique Mason, a family nurse practitioner at Hahnemann University Hospital in Philadelphia who often sees patients with a range of anxiety disorders. Indeed, a 2018 American Psychiatric Association poll found that Americans are "markedly" more anxious than they were just one year ago. And yet, just over one-third of people with anxiety get treatment, ADAA reports, likely in part because many of its manifestations are so ubiquitous (hello, lack of sleep or feeling overwhelmed) and not initially – or even ever – associated with anxiety. For example, feelings of apathy, fatigue, irritability and even anger – not just worry – can signal anxiety issues, says Kristina Hallett, a clinical psychologist and executive coach in Hartford, Connecticut. Problems that seem strictly physical like headaches, chest pain, numbness, rashes, hair loss and more can be linked to anxiety disorders, too. That's not to say these symptoms are always or even usually due to anxiety, or that anxiety as an emotion rather than a psychiatric diagnosis is a bad thing. "Anxiety is a normal part of the human experience and, in many ways, evolutionarily valuable, helping us to survive and thrive" by keeping us alert to potential dangers, explains Dr. Zachary Kelm, an osteopathic psychiatry resident at Ohio State University. But anxiety disorders can disrupt your daily life and warrant treatment, which is highly effective. The first step, though, is recognizing their symptoms. Here are some lesser-known signs that what you're experiencing may, in fact, be more than run-of-the-mill anxiety:

Your muscles are sore.

Even though she's learned how to expertly manage her anxiety, Genova still catches herself clenching her jaw, neck and other muscles – a common experience for people with anxiety whose bodies are trying to prepare them to take on a perceived threat. "I'm always gripping the steering wheel – I have sore muscles, I can feel it," says Genova, who wears a mouth guard at night to help treat her anxiety-aggravated temporomandibular joint disorder. People with anxiety, too, can also experience muscle twitching or weakness for the same reason: Their muscles are recovering from the tension, Hallett explains. Outside of practical solutions like mouth guards when necessary, becoming aware that you're tensing is key to combating this symptom and anxiety in general, Genova says. Exercises like yoga can also be helpful to ease anxiety-related sore, tight muscles, she finds.

You hate 'relaxing.'

If the idea of chilling out stresses you out, you may have an anxiety disorder. "When I'm trying to get in relax mode and watch TV … it's hard," says Genova, who also catches herself clenching her teeth in that situation. "Relaxing" – like sleeping – can be tough for people with anxiety since the lack of cognitive distraction can free up their minds to ruminate, which only reinforces those negative thought patterns. "If I'm ruminating or worrying because I'm anxious about something, what I'm literally doing is increasing the speed and accessibility of that particular anxiety pathway," Hallet says. That's why anxiety treatment often involves practice recognizing and replacing those negative thought patterns with less-threatening ones. When Genova, for one, feels anxiety symptoms coming on, she may tell herself, "I recognize this is anxiety, my body is trying to protect me … but I've experienced this before and it's not going to harm me."

You yawn a lot.

Yawning can be triggered by plenty of things including, of course, a poor night's sleep. And a poor night's sleep can be caused by anxiety. "Anxiety causes the mind to race, often leading to sleepless nights. Then, not getting enough sleep can exacerbate the [daytime] symptoms," Mason says. But anxiety-related yawning can also be unrelated to sleep: "Yawning is one of the body's relaxation methods to go the other way from the physiological stress response," Hallett says. She recommends people with anxiety practice "square breathing," or breathing in for four counts, holding for four, exhaling for four and holding for four. During each four count, "draw" one side of a square – your finger making the shape on your leg or a table will do – to occupy your mind just enough to center you, suggests Hallett, who also endorses the free app Breathe2Relax for folks who want a digital tool to guide them through deep breathing relaxation techniques.

You often feel dizzy or like you're going to faint.

Kelm says some research suggests when patients show up to the hospital or doctor's office with dizziness, up to 15 percent of them may have a psychiatric disorder – particularly an anxiety disorder. That may be because the areas of the brain that cause anxiety tell the vestibular system – the system that senses where your body is in space – that something is wrong, and dizziness results to try to "correct" your perceived ill-positioning, the American Physical Therapy Association's Section on Neurology reports. In addition to other anxiety management techniques like cognitive behavioral therapy and breath work, support groups can help with this symptom, which is often brought on in social situations like public speaking, finds Genova, who's been running anxiety support groups for years. "You need to be facing your fear," she says. "Being in front of a small audience [helps], and you're also working on it together."

You have a sensitive stomach.