<human>: Hi, okay so I may be jumping to conclusions but I'm really scared right now and I need advice.

So I am 16, female, going to be a senior in the fall, and I'd say I'm an above average kid, with a 2200 SAT and want to study engineering. I've been dating the same boy since freshman year, we're the same age and he's my best friend. We have a wonderful relationship and are close but not attached at the hip like some kids my age. Last summer, I lost my virginity to him after a long time discussing it. We had sex only about 4 times after that. The most recent of those times were May 28, where he did not come, and June 14, when he did. Both times we used a condom, and we were really careful with it.

I usually get my period about the 20th of each month, so the past few days I've been really stressed out over it. However, I could very likely not be pregnant- I am an intense (like being recruited) runner, and I have recently upped my training a lot- I added an hour of swimming to my daily (4-8 mi) runs. I have been eating enough to keep up all the exercise, but maybe it has not been enough despite what I thought. But my mind keeps floating back to the idea that I'm pregnant... and I don't know what to do. My parents are crazy strict, so if I told them what I thought, my life could be over... and I dont want that. I'm scared and confused and I just need someone to help point me in the right direction with everything.

Could you distill the essence of the text into 1-3 sentences?
<bot>: I lost my period due to being either athletic or pregnant and I am not sure what to do or who to talk to.