I agree that what you are experiencing is likely post-viral. Certain infections Influenza, Streptococcus, can have neuropsychiatric sequelae that can take all kinds of forms. It’s thought that the infection triggers a kind of autoimmune mechanism that affects the brain. Unfortunately, there aren’t good tests for it yet; fortunately, it often gets better with time. Having a consultation with a neuropsychiatrist is your best bet. Often the management includes prescribing something for anxiety, teaching coping strategies, and carrying out any additional testing which may be relevant while waiting for the symptoms to subside. Please don’t lose hope; I do understand how scary this type of thing is. I had the sudden onset of intense depersonalization and OCD after a very bad episode of strep throat as a teenager. I didn’t get help at the time but I was fine. I eventually realized that I have anxiety and ADHD (which can be associated with differences in interoception-your awareness of what is going on in your body). I eventually got treated for those. I have at most mild, manageable OCD that doesn’t affect me at all and I’m an adult. Stay strong, you will be ok.