Confused ... help?

So to sum things up, I have a 7 months old. I've been exclusively breastfeeding for the past 7 months and didnt have a period until the beginning on January. I'm not on any type of birth control, cause I didnt want my milk to go away and the 2 types I did try, I was constantly bleeding while on it. But we did use the foam spermicide as a back up. Fast forward to February when my period is suppose to be due ... nothing. I'm 3 days late. I've taken several test and they come back negative. I did stop breast feeding in the middle of January because my son just was not interested in it anymore. Maybe that has something to do with my period not showing up? With my first son I had a regular period by 3 months pp. So I'm kinda lost this time around and not sure what's going on. Have any of you other ladies had this happen? Could I be pregnant and it's to early to test or is this just my body gettings figuring itd stuff out cause I stopped nursing?