weird period

Eboni

So I had my period come on about 2 days late on the 15th but it only stayed on 3 days instead of the normal 5. Now my left breast literally aches all day and I get random waves of nausea. I don't think I'm pregnant, but I have some friends say they found out they were pregnant after having a wacky period. I just don't want to waste a test after I had what I thought was a "period". Should I?