Highly unlikely that you have HIV. Most doctors agree that in the U.S. and Canada, the common form of HIV is very unlikely to be passed from a woman to a man in conventional sex. (Edit: I just saw you are from Australia… I am not sure about the HIV strains that are common there…)
Herpes? That sucks, too, and is much more likely. Based on what I know about it, I would rather have almost any other non-life-threatening STD. I hope it isn’t herpes, but I am glad you went to see a doctor. One way or the other knowledge is power.
One other thing to note: If you do have herpes — or whatever is causing the lesions — now you will be a candidate to get infected with HIV from a woman, because any “open wound” does make the virus much easier to transfer…
Good luck!