I have taken Doxy several times now and usually end up discontinu...

I have taken Doxy several times now and usually end up discontinuing use because of strange side effects. Once because of intense burning of my skin (lasted several days). Another time because of disorientation and headache. Now I am taking it for a sinus infection. Giving it one last shot. I have only taken two doses, one last night and one this morning; and I am already extremely nauseous and lightheaded. My doctor told me if I dont finish this, my infection may turn into pnuemonia. I guess i will suffer through it.