it is extremely unlikely your gf caught HIV
from her other partner. Therefore, your symptoms
cannot possibly be due to HIV
. Period, full stop, nothing more to say. See a health care provider if you remain fearful despite this reassurance.
I know you are anxious, but I'm trying to tell you why you should not be. It is frustrating to reassure people and for them to argue with it! Just accept the reassurance and move on.