Will birth control stop my period? Other birth control q’s????

I’ve been directed by my gyno to start my birth control the Sunday AFTER my period. But I’m suppose to see my boyfriend next Tuesday and I want to have sex however my periods last like 10 days & my cramps are so bad and my flow has been so heavy I just can’t take it anymore to wait the Sunday 😭 so if I take it now will it still work/be safe? Will my period stop? How long do I have to wait for it be effective to have unprotected sex? Forgot to mention I’m taking the combination pill