Help! I am afraid I might be pregnant

In September, I took Plan B. My period came very lightly a week later (on September 15th). After that, my boyfriend and I had sex on October 27th. My boyfriend wore a condom and did not finish inside (but I qm afraid some precum might have leaked). On October 30th, three days later, my period finally came. This time, it lasted about 4 days but came with a very heavy flow and a lot of cramps. Today is December 19th, and I still haven't had my period again. Is there any risk that I might be pregnant? Why is my period taking so long? I haven't had sex since October 27th

I had taken a pregnancy test in October, but it was before my boyfriend and I had sex on October 27th. This week I felt some cramping and some tenderness in my breats , but no sign of my period. I am afraid.