Hello. I know I'm probably being extremely silly but I just want some advice.

Some info about me first: I am usually very regular, the most I have ever been off was about 4 days (early, not late). My boyfriend and I were fooling around and we were both naked and he was rubbing himself on me. He was right near the clitoral hood (sorry if TMI) when he came prematurely, but he pulled me off in time. We quickly wiped it off with a tissue with soap and water (sorry for tmi again, but the cum was in the hair more towards the mound and not the opening). I keep track of my schedules and I was pretty sure that it was about 4 dpo when it happened. A week later, I got my period and it was seemingly normal, but still lighter than usual (stopping on and off) and lasted for my usual 5-6 days (the last day was brown spotting which is normal for me). I am not on any birth control. I went to the doctor to get my HPV shot about 1 week after the first day of my LMP (making it 2 weeks since the incident), and she gave me a urine test, which was negative. I'm still a little paranoid though, and I'm not going to lie I have a reputation of being a hypochondriac (i hear about something and then i automatically have it). I'm due for my period in a few days and so far I'm PMSing pretty bad (really bitchy and emotional, my normal cravings, boobs a little tender but not really. Also, I am pretty sure I ovulated recently (lots of EWCM around CD14-CD18, increased libido, ovulation pains, breast tenderness)

Other symptoms I have been having are:
fatigue (I rarely sleep more than 6 hours and sometimes get as little as 2 because of schoolwork)
increased appetite (I wasn't eating for about a month so I guess I should be hungry)
chronic headaches (very bad eyestrain and enormous amounts of stress and sleep deprivation
Moodiness (stress, sleep deprivation
backaches (I carry a very heavy bookbag and slouch a lot)
A few veins have been appearing on my breasts (although my boyfriend says they have always been there, and I am pretty pale)
Heartburn (family history of acid reflux and hiatl (sp?) hernia)

I just want to know if there is a high chance that I am pregnant, since I have had a period and a negative pregnancy test. I know the dangers of precum and I feel really stupid for getting caught up in the heat of the moment. I have to admit that I am only 16 years old, but I do want to become a fertility doctor so naturally i take a lot of interest in this stuff. My mom knows that I have had sex in the past because I have a very open relationship with her. I am a very good student with a high average, but lately unable to concentrate while worrying about this. To clear up any disputes, i am pro-choice and might have to abort the baby if i am, simply because I am not healthy enough to carry a child). Your advice is much appreciated, thank you :-)