How accurate are HIV tests after 7 months?

Back in may of 07, I got cut at a manicurists. So in december of that same year, I had an HIV test. I got my results on january 17th, it was negative. I'm asking this because, for about a year now, I've been experiencing abdominal pains, diarrhea/constipation, sometimes when I go to the bathroom, all that will come out is this fatty mucus stuff, not even stool. I also have been getting chronic fatigue, body aches, muscle cramps, tingling in my extremities, the scale says I haven't lost anything, but my clothes are noticeably looser, depression, anxiety, joint pain, ataxia (loss of balance), and a whole bunch of other things. My celiac levels were slightly elevated, as was my WBC count. My blood pressure was a little low. Someone also mentioned the possibility of candida overgrowth. I do have a lot of the symtoms for that. What causes candida overgrowth? I heard that the overuse of antibiotics can cause it sometimes. I took some antibiotics in march last year for an ear infection.