Should I take Plan B?

Last month, I missed three of my pills in three days in a row. And my period came on like three weeks early so I didn't have no idea what to do so I took my placebo/sugar pills for the rest of the week. I went back on the same pack active pills.

From there, I started my new pack once my old one is finished. Of course, mid way through my new pack of birth control pills. My period started but I kept taking my active pills until I got to my placebo pills for my actual period to start.

Recently I had sex(Last night) with my boyfriend last night and it was unprotected. Should I take Plan B since my period have been bit irregular?

Going over this basically, my period started early by three weeks and I had unprotected sex.