Running with jiggly belly....what is this?

Ok I've never had a jiggly belly I started back running today and the fold or flappy thing feels like it's jiggling? Why is this? How do I tighten things up? This is driving me crazy. I'm up for any suggestions but mainly want to know from other runners if I'm alone and is this normal?

Hi there, not a runner, but a cyclist. And I had the jiggles a lot! My Doc sent me home with a binder, then I switched to a boned half corset thing called a waist cincher. Finally I just wore a compression t shirt. You will find what works for you and I hope you'll be feeling right really soon. Love, AW