Whole foot or just a bit of the foot? Any other joints infected? Any injuries in the past? Any family history? Any X-rays? Do you jog?
I certainly wouldn't throw in the career at this stage unless you had very good specialist advice. My guess if it's just one joint that is affected is that it relates to an injury - possibly even an old one that you've completely forgotten about. There are other possibilities such as stress fractures as well. And there are treatments for various conditions - heck, you can even get joint replacements on toes if needs be. If it's causing you this much grief at your age and has lasted that long, I think you need to see a specialist and get a firm diagnosis.
If you're taking medications, also consider topical ibuprofen or diclofenac gel (don't you need to consult with your AME even if on paracetamol?). Everything has its side effects and whilst it's reasonably safe, Ibuprofen will put your blood pressure up a bit and can give you stomach upsets and set off asthma attacks (if you have asthma). If you can make do with less, all the better.