My Periods Are Anywhere From 4-6 Weeks Since I Had

My periods are anywhere from 4-6 weeks since I had my son 14 months ago. My last one was beginning of November sometime in the first week. So I have been waiting for my period to come now since it's been about 5 week or so. I had rough sex with my partner on the 8th on the evening and woke up in the morning on the 9th to bleeding. 8 assumed it was my period starting. I bled not as heavy as usual but still enough to use a few tampons. By the evening of the 9th I stopped bleeding. The next morning I was bleeding semi heavy again and now the next morning it is lightening up again. Do you think this is bleeding from sex? My periods are usually 5-7 days long. I think I might be pregnant as well.