Ok, I have had my last 3 periods but they've been very irregular and they are usually very regular. Almost 4 months ago I had unprotected sex but he pulled out. I have very sore and swollen breasts, a semi-stiff lower abdomen, nausea, and I am very tired all the time. I took a hpt a couple months ago and it was negative. I've gotten told that if i've had my period not to worry about it. Could I be pregnant?