Three kids is going to take a toll on anyone's body, no matter how good of shape they were in previously!

Can you find a gym or a trainer or something and maybe get your measurements, body fat, etc, so you have some objective data as to whether you're really "huge" or not? I'm famous for my skewed perception of myself and it really helps to have people point out things I don't/won't see or give myself credit for.

Once you know for sure you have something you need to work on, then you can go about addressing it.

Maybe think about finding a therapist too, who specializes in this kind of stuff and can help you learn new ways of looking at yourself.