HIV Positive/Western Blot Negative

So I got a call from my doctors office saying that my bloodwork came back as being slightly HIV positive so they ran a test that would make sure called the Western Blot. The Western Blot test came back negative which the nurse said means I am HIV negative (thank goodness). So I did some research on this and there are multiple sites saying this could be linked to things such as Lyme's disease, syphilis, and lupus. So as you can imagine I am freaking out. They said not to worry, me and the baby are fine, but I am just wondering if this has happened to anyone else??