I’m worried I may be pregnant

I had unprotected sex on January 4th and he pulled out and I took a look plan-b. My period came the week after next but now all I e done was spot a few times. My period hasn’t come down in about two months and I’m getting worried. I’ve done some research and it said that the plan b could’ve thrown everything off but idk. I used to take birth control to regulate my period but they took me off of it. Please someone help.