I started my period on the 3rd, it ended on the 6th, I had unprotected sex on the 7th and my fiancŽ did not pull out, I am usually a 30 day cycle, I started on the 15th what seems to be a period but only light pinkish spotting and only really noticeable when I use the bathroom and use the tissue. I'm not really sure how ovulating works as I have read that imbalance of hormones and obesity could affect that which I am both. Just worried I am also 36 year old

Since it would be early for a period, it's possible it is due to ovulation which generally occurs about 12-16 days before the next period is due. Some women, however, will ovulate a bit sooner or later as a norm. On occasion, some spotting may be noticed.

See if a period starts up more like a normal one for you. Otherwise, see what happens when you would expect your regular period. While conception would not be the norm from sex the day after a period ends, it can indeed happen. If you hoping not to be pregnant, be sure to use protection every time no matter what time of the month it is to lessen the odds.

I will agree, while the "odds" are against pregnancy.
** You do know that pulling out is not a real method that has much effect ? Since there is plenty of sperm in the early fluids.

So at this point, you have to wait till the next scheduled period and see if you miss it or not