What was that!?

Daniellemf1228

I was laying in bed this morning and rolled over to my back.  I felt like a weird pulsing/pulling feeling and put my hands down to my belly button.  Right there just underneath to the left of it my stomach was hard as a rock and raised up like a lump larger then the rest of the area. It started to feel less hard and then kind of leveled out with the rest of my stomach.  

What was that? Anyone had anything like this before?