Regret and guilt are the main problem you seem to have because you do not describe any symptoms. You received oral sex and licked her some as well, correct? This poses minor risks for std's. In the off chance the woman had gonorrhea or chlamydia of the throat, she could pass it to you giving you oral. Herpes is another but this would be herpes simplex 1 or oral herpes. Did she have any sores on her mouth? And this is not very common to have happen. Hpv and syph are considerations as well. But all are low risk. In the absence of symptoms developing, I would not worry. Doctors in the field usually do not recommend testing after a single exposure like this unless symptoms develop. And with regards to HIV, that is no risk at all. General bacteria? Well, not sure what you mean. Could you get a virus from being in close proximity to another human like flu? Sure. You can do that at the grocery store too though. Licking her is not really a risk and would not be of worry. If you develop a blister or discharge, then go to a testing center. But I personally would not be very worried about your encounter. Use a barrier next time though.
This is an older thread by a doctor that is famous in the field. Copy and paste for his thoughts on oral sex and testing.