Late starting pill pack

Hi! So I’m on a combination pill, been taking it for abt a year now. Me and my partner had sex two days ago and i started my period (withdrawal bleeding) that night. No condom but he pulled out. My local pharmacy has been closed for several days now and I haven’t been able to get my new pack. I’m supposed to start the new pack tomorrow but I will be late starting it. Should I take a plan b? I know that sperm can live in the vagina up to five days and do not want to risk pregnancy. Thanks!