Question....

Renee • 33 yr old FTM with soon to be 10 yr old daughter. Have a 13 yr old "bonus" daughter and our 🌈 daughters, A'Siah & A'Riah, EDD 10/10/17
Anyone experiencing tightness at the bottom of your stomach? 
I.E feels like a rock for a quick second 
It's not the whole stomach, just where the babies are positioned. Currently 16 weeks with twins. My babies are in separate sacs but possibly in same placenta. Dr haven't confirmed just yet. I don't go back until May 18th for the anatomy scan and to find out if they share the placenta or not.