What Causes Scanty Periods With Stomach Cramps?

Hello, I had my period at the beginning of this month (or what I thought was my period) and it lasted a day and a half, since then I have had very minor lower stomach cramping day and night, and the past few days I ve had random stomach pains all around my stomach including the light cramping still. My periods are never that light, nor have I ever experienced stomach cramps AFTER my period, especially going on 3 weeks later now. I am also experiencing problems going to the restroom lately, my breasts have had random sharp pains (never happened before) and I have had a terrible time getting to fall asleep like I normally can. Is there any explanation of what could be wrong?! Please help!