Plan B & periods???

Al
I know plan b can mess up your period but I need to know how normal (or abnormal) this is. I had sex around ovulation day. Protected and be pulled out but we didn't check for rips. I'm really anxious so I bought plan b 36 hours later. It's now 2 weeks later. My period came 2 days before it was scheduled. It started off normal and gradually becoming heavier. Heavy enough to go through a pad and use tampons. This lasted for about 2 days and now it's just pretty light with some brown when I wipe and I'm having a cramping/pulling sensation on my left side. My periods usually last 5 days and are usually a couple of days late. Is this normal? Could this be implantation bleeding or another early pregnancy symptom?