I was put on doxy and started feeling better, then about 3 days in I had super sharp pains in my neck and in my back (didn't know what was going on at this point) then after about 10 days for like 30 mins in the afternoon I would feel like I was coming down with the flu and then get a mild fever and then...I'd be fine. 30 days of doxy and I was almost back to normal.
Unfortunately right after I ended the doxy symptoms started coming back and worse. That is when I went to an LLMD who put me on the right medication. I hope you start feeling better soon. In the meantime I would look for a Lyme Literate dr - there is usually a waiting list. I was okay but *** hit the fan in january, unable to work etc. but luckily I had an appt already set up. Right back on abx and I was back at work. Don't hesitate to ask questions here.
When it is at the point where it is late(r) stage, it would be unusual for 30 days of low dose doxy to do much of anything, I regret to tell you.