Jess,
Your various symptoms point to red blood cell problems, but possible causes range from an infection to bone marrow issues. Atypical Hemolytic Uremic Syndrome, which can result from genetic problems, environmental problems, or a combination of both, is dangerous because of possible clots in the kidney, so it's good news if that was a false reading or somehow temporary.
I think you'll find that webmd.com has good explanations of diseases and symptoms that we laypeople can understand, but I suspect that you won't be able to pinpoint this on your own. The doctors will have to keep watching and testing you to come to a firm diagnosis.
Aplastic anemia is only one of the possibilities. If that turns out to be the case, these forums and the
Aplastic Anemia & MDS International Foundation have people and resources to help you.