My gf and I basically had unprotected sex on August 2nd. However, when we tried doing it, my penis didn't go in all the way, if at all. After trying to put it in her once, i looked down and i was dripping some precum and stopped. She took Plan B about a day and a half later. We're both freaking out that she could be pregnant. She's expecting her period this weekend (August 16-18) but we're both really worried because she felt like her period was already supposed to have came. Any input?

If this helps: I ejaculated the night before but peed numerous times, including a certainly long one right before we did it.