Unprotected sex

My girlfriend and I had unprotected sex Friday. I only went a few minutes to try it then I went and out a condom on and finished inside. An hour later we did it again and I didn't cum at all. The third time we did it again and put a condom on and finished inside the condom. 
She took plan b but threw up 2-3 hours later that night. She is suppose to start her period today, but hasn't and doesn't have any bloating or cramps like she usually does.