If her vagina just touched your mouth for a couple of seconds, there is no risk. There is no need to be so worried.
Even if you had performed oral sex on her, that's considered low risk. Most experts don't think an act of oral sex warrants testing because it is so low risk.
There's nothing to worry about. If anxiety is the norm for you, you should talk to your doctor about it.
Highly appreciate a response. I am worried sick at the moment