Hi Frank,
welcome to the forum!
Like MrsPallas said, if you are up to it, please read the entire 'New to Lyme?... Start here!' thread. It will give you the much needed information to start your journey.
It is encouraging to hear that your primary care dr is very supportive and that he did the testing. I must add though that 200mg of Doxy will not do the work of killing those bugs, you might feel some die-off, but it is more like a maintenance dose. I for instance got it, when I was on a break from my abx protocols, to prevent the bacteria from multiplying. You will need double to make it efficient.
Also, I would recommend that you look for a LLMD (Lyme Literate MD) who will have more knowledge about these infections. Unless your primary care dr knows a lot about Lyme and it's coinfections (but I doubt it, considering the low dose of Doxy he put you on). In my personal opinion, you will have to look for someone with a lot of experience with Lyme disease.
If you decide to go see a LLMD, you can start a new thread 'Looking for LLMD in ____' - be sure though to enable your email address so people can send you the requested info by pm, we're not allowed to put dr's names on the forum.
One of our moderators, Traveler, had RMSF, so she can give you advice on that.
Since you feel so bad, can I ask you if you started detoxing? Detoxing is an important part of your treatment, you can find lots of info on it in the 'New to Lyme?... Start here!' thread. And of course, feel free to ask us questions whenever you feel the need, or just vent if necessary...
Good luck!!
MarieLS