Sorry for the uppage, but I noticed that none of the prior responses touched on how she's feeling.
I have two friends who have genital herpes - both smokin' hot women who attracted the wrong kind of guy, who lied to them about being disease-free.
Both have serious self-worth issues as a result of it; one said to me, in tears, "No guy will ever want to touch me again".
From the very limited aspects of the tale you've given us, I don't feel like she's been a very good friend to you ... but if I try to see her acting within her own insecurities and emotional response to carrying this disease, she makes sense to me. Your "rejection" would have been more hurtful to either of my friends than it ought to be, logically, and especially if you used the very thing they're afraid of rejection for as a reason to reject them.
If you had a close, long-standing friendship, I'd think that you might have every chance of being able to approach her one or two weeks later and say, "Look, I miss your friendship, and I'm sorry that I hurt you, I'd like to talk about it."
On the other hand, if you had a growing-but-not-yet-solid friendship, its possible that she was more attracted to you than she let on; again, this might help to explain why she was more hurt by your interaction than you might have expected. In that case, maybe its best to let it go.