early cramps?

I'm on the pill and the week of my period I usually get cramps but they've started earlier the week before my period. eve predicts it's supposed to start on Monday but I've have tiny cramps since Tuesday or Wednesday I just woke up and they are stronger now. The only pill I missed was one fake pill in my last pack and I've taken my pill a few hours late. If I did miss any others they were doubled up the next day. Should I be ok? I'm hoping the cramps are just because the period is coming not implantation cramps.