Hi,
I have an autoimmune condition called Seronegative Spondyloarthritis and take a couple of different types of immunosuppressants to try and keep the inflammation in check.
It does sound like you have a good few things going on, and I agree with everyone else that going to the GP is a good starting point. If I were you, I would make a list of your symptoms and how long they have been going on for, and even keep a symptom log for a few weeks so you and your GP can identify any potential triggers for symptoms. I wouldn't necessarily say to your GP that you are worried about an autoimmune condition, but rather something along the lines of "these symptoms have been going on for quite a while and I am concerned that there may be an underlying reason for them, can we check things out to make sure everything is okay", and then you could bring in if you have a family history of autoimmune conditions which might help to rule things in or out. GPs are usually quite happy to run a full blood count which looks at various levels, and to do some preliminary investigations which might help guide them to what is going on, or to referral to particular specialists.
I'm sorry you've not been feeling well - I hope you get some answers soon. It took me 8 years to get my diagnosis.
Take care,
Physiogradmed