please help...really scared "herpes"

hello all,
I just noticed a few days ago that I have a red lump under my pubic hair that is sore when you push on it...I haven't had sex in some time, but am curious if this could be pubic herpes...what symptoms should i be looking for...i'm just extremely scared...i can tell that it has been getting bigger...i haven't had sex in around 3 weeks, but have messed around with someone...she had boxers on and so did i...i was on top etc. I'm just terrified that she gave me pubic herpes...does this sound like it? any help anyone...i'm begging