hi stress would be one of the things to stop your periods. unless it was some kind of magic sperm did he ejaculate in his pants? if not you would not be pregnant it takes full sex intercourse to get pregnant. look its not so much hormonal changes but your hormones even at 16 can get out of whack a simple blood test at your doctors would tell all when it comes to hormones. if your around day 14 of your cycle it could be a day either way but this is ovulation day so are you at this part of your cycle? good luck
it has been wierd because idk my cycle and since changes are coming it can easily confuse me and could stress cause. could stress cuase me to think i am pregnant. because i could be ovulating. but i feel strange although i havent had sexual contact. with the boy we jus dry humped with underwear on i'm not sure if this could cause pregnancy or is this normal hormonal changes becuase i am 16 now