Pregnant?

I'm almost a week late on my period. I am always very normal. I've had slight cramps off and on for days that make me think I'm going to start today because that's how it has been in the past, but not this time. Is that normal? I worked out 2 days last week for the first time in a few weeks, so could that...a change in my diet/routine be what is making my period do this?