Stopping birth control pill

I've been taking yaz for almost two months but the side effects are just too much. I am having severe itching all the time which I see is listed as a severe allergic reaction. I have found another forum with women talking about having the same problem.

I want to stop taking it immediately because it is getting too uncomfortable.

What I would like to know is of you stop birth control midcourse, can you get pregnant from unprotected sex you had earlier while still on the pill? Since sperm can live up to a week, How many days do you need to wait to stop the pill after having unprotected sex to ensure you don't get pregnant ? Or should this not be an issue so long as you took the pill daily during the time you were sexually active?

Thanks

Thanks