Many symptoms of Lyme and fibro are the same so it's difficult to tell. I will tell you that I have a summer-long flare every year because I live in Florida and the humidity and rain do it to me every time! So, yes, flares can last that long.
Ask on the Lyme forum for a list of Lyme-literate doctors in your area. They will help you that way. I wouldn't see the one you went to. Go with something that is proven to help with Lyme. They can send your bloodwork to Igenex labs in Palo Alto, California, which is the most accurate lab to diagnose Lyme. If you have Lyme, a proper treatment will then be determined. But, the Lyme forum can really help with that.
I wish you luck in getting relief. Yes, please do check out your medications. They can cause problems, too, as Mrs. Mike alluded to. It can't hurt to check it out. Please let us know what you find out because we really do care about you.
Sherrine