Why do my gums stick out so much?

I've never seen gums like mine. My teeth do overjet and I'm doing Invisalign for that, but even looking online for photos of overjets, I don't find guys that stick out as much as mine do. It seems the gums themselves have an severe overjet and even worse, then a gap where they end that cause very unattractive outline shadows around my lip. What is this and how is it corrected?