Thank you for your post.
You can't get pregnant from dry humping. There is a risk of pregnancy when a woman has unprotected sex with ejaculation inside her vagina or (more rarely) on the opening. Accidents can happen, so it’s best to use protection during any genital to genital contact. Then you won't need to be worried. A period is not the same as implantation bleeding which is typically light brown/pink spotting over 1-2 days. It's not the same as a period.