Lots of new meds / plan b

So, last week my boyfriend and i had sex. we didn’t use protection (oops) but he pulled out right before he climaxed. so the next day i took a plan b just to be safe. i’m supposed to start my period within the next few days, but ever since my last period, i’ve been soooooo irregular. not to mention, i’m on 5+ new medications, but i’m not sure if that will have anything to do with me being late.