Since i've gained waight i have a smelly liquid coming from my belly button. it is also red inside?

Need cleaning: The belly button is a great hideout, it's difficult to clean and some secretion might accumulate. Needs to clean possibly using soap-water and a qtip, carefully if is red inside.

I think you: Have an infection inside your umbilicus, maybe a fungus infection. Show it to your doctor and if it is a fungus infection get tested for diabetes while you are at it.