ANY IDEAS/ADVICE!?

Rachel • 23 year old stay at home mom have a energetic 2 year old son and pregnant with di/di twins due 4/17/16.
I've been TTC baby #2 for a few months now 
On Monday Friday and today I have had some mild cramping and AF isn't due until 7-11
Any one have any idea what's going on? I'm afraid I'll be staring my period really early or something.
Here is just my chart
Could I cramp from BDing to much?