pregnant or not?

i'm having worries whether i'm pregnant or not tho i already had my period. i did it with my bf last oct. 31 without condoms nor pills or whatsoever. he didn't even release inside me (he didnt at all) . but my concern here is that im not sure if im safe that day and i've read articles about pre-ejaculation that there's a possibility that a woman can get pregnant of it. the next day i observed a droplet of blood on my underwear then on nov. 2 i had my first day of menstruation. it's weird since i didnt experience pain on my breast as a premenstrual symptom and plus i didn't also feel any abdominal pain during my period. today is supposedly my 4th day but then i've noticed that i already stopped bleeding which worries me more because i usually have 5-7day period. i'm not sure if there are hormonal changes that can be the cause of my worries since last week i've started doing exercise routines and i eat less than usual now. those articles about 'menstration during pregnancy' alarms me more and more. i'm not planning to get pregnant anytime soon. help?