Thought losing weight would help

I’ve lost 55 lbs since I had my baby... I’m only 105 lbs now. All my clothes are too big on me. I barely fit in a size 2 jean. Yet my stomach still looks like this when I lay on my side. I don’t get it. How can I get this to go away? If I lose any more weight it’ll be unhealthy. I can’t wear any bikinis or anything because when I sit or lay down my belly button turns into this weird crack??