Messed up taking my birth control, need to know whats happening to my body.

Patient: I’m 18 years old and have been on birth control for 3 years. Last month I ran out of refills on my birth control and had to go an entire month without it. Me and my boyfriend still continued to have unprotected sex. I finally got my period five weeks after my previous period had ended. This month Im back on the birth control but i missed three pills in the first week of the pack then got back in the groove of taking it regularly again. Im in the third week of the pack but I have started bleeding almost as if im having another period. I just need answers.