I know others will be along to welcome you to the forum, direct you to resources and offer feedback. But, I'm glad you found us.
I can tell you that my experience was very similar to yours -- and I have Lyme, Bartonella and Babesia (the latter are co-infections of Lyme that you can also get from a tick bite). I had a large, circular rash on my left calf. Mine was slightly bluish in hue and was slightly tender to the touch. It faded over the course of a week to ten days.
1 to 2 weeks later, I had a flu-like episode where I was in bed with chills, severe headache, body aches, etc. In the months that followed, I had many of the symptoms you've outlined.
My PCP misdiagnosed my rash as a spider bite. Several months later I pushed for a Lyme test (the first is called an ELISA test), which came back negative. The tests are unreliable. A few months later, I went to the ER with a severe headache and a spinal tap revealed Lyme via a Western Blot test (which is a slight better, though also imperfect test).
My point here is -- yes, this very well could be Lyme and a co-infection like Babesia. The best way you can evaluate your condition is to find a Lyme Literate MD that can assess clinically what your symptoms reflect and rule out what they don't. They will test as well, but seeing someone that understands and responds to symptoms is really important.
If you need help finding an LLMD, others here can offer suggestions based on where you live.