Pregnant or irregular

My boyfriend and I recently started having sex. On June 10th we had unprotected sex. I took a pregnancy test and it was negative. My period was a few days late after that (scared me but I’m good). My period came on July 5th and lasted til July 10th.

Now it’s August 27th and my period is 16 days late according to Flo (I just hopped on this app yesterday)

2 days ago we had unprotected sex again (we have condoms, just didn’t use it.... We’re dumb I get it) but this time he got worried cuz it seemed like he came inside of me. He said that when he pulled out some cum just dropped from his dick and he said “oh fuck”. Keep in mind we were doing it for no longer than 30 seconds at this point. He has never finished that fast with anything else we’ve done or by doing it himself. I tried pushing it out but he said he didn’t see anything coming out. Then I peed thinking maybe that pushing motion will let something come out.

25 hours later, I took Plan B One Step (95% effective). It’s now the day after taking Plan B.

Anyone ever have this situation?? I feel fine, my period just isn’t coming. Last year around this time my period was super late so maybe I’m just perfectly irregular? I would say “what if I’m pregnant” but my period was already late before I had unprotected sex the other day. I just don’t know why my period is so late.