PLEASE HELP!!!

i was meant to start my period about a week ago. i was also fingered by my partner and i gave him oral sex after he had fingered me, around the time i was meant to start my period. he released his sperm in me, and i know you cannot fall pregnant from swallowing semen. is it possible that because i was fingered my brain thought i was having sex and released the egg to be fertilized with the sperm, but no sperm came. i've been having period-like symptoms, and when i did the cervix test (my cervix is low, and hard and open, to release blood), i should technically have menstrual bleeding, but i'm not. i'm so worried.