My period stopped on the 3rd day, it usually lasts 7 days. 6 days before it came, me and my partner only rubbed genitals naked (but maybe precum is present). my period came on time, i had pms and severe cramps on the 1st day. i wonder why it stopped?

While intercourse is typically needed for pregnancy, there are isolated cases involving other sexual activity. Take a home pregnancy test to determine if you are pregnant. Unlikely, though since you did have a period. (length of periods can vary depending on stress, lack of sleep, increased exercise, weight changes, etc which cause hormonal fluctuations).