You may want to check out this linked post. It has an attached pdf regarding useful supplements and herbs.
Also, don’t let doctors dismiss your symptoms as “nuisance diseases and not life threatening”. There are lots of disabling diseases that are not life threatening. If you can’t complete activities of daily living, it’s a bit more than a nuisance, isn’t it? It affects your quality of life rather substantially. Push back on that when doctors try to dismiss your concern. I’d also make sure your school knows you have a medical condition that could impair your ability to finish your exam. I don’t know what the law is exactly in the UK for people with disabilities, but they should accommodate you.