I'm not sure what I'm feeling...

So I'm feeling pains (pretty light pains so I'm not sure it's even worth mentioning this, but I'm going to ask anyway) in my uterus towards the top left. I know when the pain is on a specific side it COULD be a sign of implanting, but what are the chances it could also be my AF? I seriously don't want to get my hopes up so I just want to know if it could end up being period pains.