Implantation or period??

I started spotting on thursday and Friday. It wasn't even enough for a panty liner. Then on saturday it got a little heavier and Sunday was the same and then Monday when I woke up I have a little bit of spotting and nothing since. I was suppose to get af on the 4th but I'm confused. My periods are usually really heavy and I cramp so bad. But I had little to none and my period last anywhere to 6 to 8 days so I just need some advice.