Pregnant or not

So last month I had unprotected sex and while we was having sex he thrusted and stayed in me for a few seconds then we continued to have sex, but then he officially came. I’m scared I might be pregnant but I took a test and it came back negative, I’ve had little to no discharge and my period is late by almost 2 weeks. The weird thing is I had 2 periods in December and that threw me off.