help!!!

I may be going crazy but I just need some help. My period is spot on every month. I'm not on birth control. This month was weird. I felt strange for a week before my expected period (I assumed it was PMS) and then my period came 2 days late. On the day that my period was supposed to start I just had white discharge. My period contained no clots or shedding and it only lasted 3 days (usually lasts 5 heavy days). No cramps or usual symptoms. Could I be pregnant? My boyfriend and I usually only rely on the pull out method (irresponsible I know) but we would be ok if I was pregnant. Please help!!!