Is it possible I could be pregnant?

Me and my boyfriend have had unprotected sex 4 times this month. 2 times 3 weeks ago and 1 time 2 weeks ago. I got my period last week though. It wasn't like it usually is. This time it was really heavy. Usually it's just really light at first and then normal, and then light again. But this time it was a lot and it lasted about 4 days. I just wanted to know if there was a chance I could be pregnant? I'm tired all the time, I get headaches now (I never used to get them), and I feel bloated all the time. are any of these signs of being pregnant? Should I take a pregnancy test? Help!!