very confused please read this

Okay so about 10 weeks ago I gave head, and as fair as I know I didn't get any cum on my hand. Then about 40 minutes later I went to the toilet. 6 days later (could this be implantation bleeding?!) when my period was due I got very light bleeding which stopped immediately. Then the bleeding increased a tiny bit the next day and then got heaven the day after that and my period continued as usual for another 5 days and was very heavy. My next period only lasted 5 days (they normally last 7) and it wasn't as heavy but to some people it would be heavy. Then this period lasted 8 days and was heavier. Now I'm experiencing a very twitchy tummy and pain when I push on the right side of lower abdomen. I was just wondering if there was any chance that when I went to the toilet  I got some cum on my vagina and it worked it's way up? Am I pregnant? If not, what are these twitches and pain? Also I've never had sex before. Also there my hands were completely dry.