Period late, pregnant, or exercising too much?

I was supposed to get my period on wednesday, today is saturday. Now, this is our holiday break so I've had more time to exercise and I've been exercising everyday for the past 9 days, usually for a little over an hour each day. And I've noticed that I lost a few pounds. And this past month I have been stressed out because of all the college applications I have had to fill out. However, I'm worried because my boyfriend and I were fooling around recently. My normal cycle works where a week before I'm going to get my period, I get cramps on both sides of my lower abdomin. But a couple days before and a couple days after, my boyfriend and I both had our underwear on, while he was fingering me. Then I gave him a hand job but he only pre-cumed. I have thought about this many times and he never touched himself first and then touched me. But can sperm go through clothes, even if it's only pre-cum? And what if I wasn't wearing my underwear but he was wearing his boxers and he was on top of me? His pre-cum was absorbed by his boxers. Is there any reason to worry about a pregnancy? Usually, a week after I get my first cramps, I get back pains and cramps in the middle of my lower abdomin. On Wednesday, I had cramps and then they disappeared. Furthermore, I am getting sporatic cramps that last only a few seconds. My period is usually irregular during the summer when I exercise all the time. But I don't know what to do. If anyone has an answer please respond asap. Thank you.