Hi, I'm a 17 year old girl in high school and had sex with my boyfriend and the condom broke but he didn't ejaculate and pulled out right away on November 23rd,I got off my period the day before. My period was due somewhere within December 14-16th. I still have not gotten my period and it is now the 18th. However, I've been in an aerobics class for school (my gym elective) for about 3 weeks. The class is pretty hard and really active/physical. The last time I really had a workout was in late July for swim practice, so my body hasn't necessarily been used to all of this physical activity but is gradually becoming used to it. We do a lot of cario and ab workouts along with "boot camp" routines. I'm 5'8" weigh about 125lbs and my body fat percentage is 18%. I asked my teacher if exercise could affect your period, since I haven't gotten mine, and she said yes. So could all of this exercise be delaying my period? If so, for how long? What are my chances of being pregnant, considering I had sex the day after I got off my period and don't ovulate until about 14-16 days after that along with the fact that although the condom broke, he did not ejaculate and pulled out immediately.
Thsnk you.

Just because he didn't ejaculate and then pulled out doesn't mean early semen ("pre-c u m") wasn't there. (Pulling out, by the way, is not any kind of a birth control method.)

We have several medical people on the site, and they will see this as they come online and will give you a reply. My guess is that there is a chance you could be pregnant (there is ALWAYS that chance, even with THREE forms of birth control). Our experts will give you advice as to how to determine if you are or not.

Could the exercise be possibly affecting?
I haven't had any pregnancy symptoms and feel completely normal

Your body fat is low, but not extreme. It's possible the recent exercise has been enough to cause a change to your cycle, although it would be more likely in someone who works out substantially more often. It could be your period is just off a bit. Being early or late by a few days is not uncommon. Cycles are more prone to being a bit irregular in the teen years as well... even if you haven't been prior to this.

Pregnancy is possible, but not probable given what you described. You had a condom (albeit it broke), he didn't ejaculate (obviously cuts way down on the number of possible sperm), he withdrew (can work well for some, but takes a good understanding of your body and it has to be used correctly... not one of the more effective means of birth control for many people), and it was right as your period ended (you could have an early ovulation, but most often it would be closer to mid-cycle).

I'd give it another week and see what happens in regard to your period. If it still doesn't show, try a pregnancy test. If negative, see what happens next month when your period would normally be due. You could try another pregnancy test, to ease your mind, before that time if your period still hasn't shown up for December.