Could I be pregnant? Help!?

Ok so my period usually last for about 5-7 days at a time. Around 2 weeks ago and up to last week my breast were hurting so bad. I thought maybe it had to do with the arrival of my period because this used to happen before each cycle except it hasn't happened in awhile. Anyway my period came on last Wednesday I mean the usual bad cramps and all. By the end of Thursday it was light and Friday it was gone. I didn't see anything over the weekend. Monday I had some sharp cramps and later on that night some light light bleeding. I don't understand what may be happening or going on. Can someone help me? Thank you