Q. Could my HIV test be false negative as I got tested after six years of exposure?

Hi doctor,

I would like to begin with my dropped CD4 count of 350, which I had six years ago. Two weeks later, it raised to 398. The doctor said it could be entirely reasonable for a woman to have a count of CD4 around 400. The reason for dropping maybe due to a previous infection and stress. I had no any infection previously, but a low-risk exposure to HIV eight months before and no further risks ever since. Last year, I had my first ever HIV test (third generation antibody), which came back negative. I also had two more the same kind of test after that with negative results. Only recently, I am experiencing recurrent colds and blocked, runny nose, vaginal infections, fungi like discoloration on two of my fingers and red dots or spots, rashes on one of my shoulders. Could these symptoms be related anyhow to HIV or AIDS? Could my test be falsely negative due to late testing after my exposure of six plus years? Should I have another CD4 count or other tests? Thank you for your time and answer.