Short and light period with nausea and pains

I'm super confused. I am 20 years old and have a 9 month old daughter already. With that pregnancy I got the extreme symptoms and there was no mistaking the fact that I was pregnant. Now I have had a feeling for the past few months that I'm pregnant but the only thing is, I've been having what seems to be my period. I always have had atleast 5 day periods, never shorter and quite heavy. The past few months my periods have only been 3 days and extremely light. I have been getting abdominal pains along with cramps. They feel like Im being stabbed from inside and the pop up everywhere. I have been having unprotected sex, but using the 'pull out method'. There have been a few times where he came inside me though. I am constantly tired for no reason and I get nauseous at random times lately. Is it possible that I can e pregnant? Has anyone had this happen to them and turn out pregnant? Please give me some feedback. I'm so confused!