I've gone from an 18 to a 26

I'm huge and I hate it. But, I'd rather be fat and on meds than skinny and crazier than now, if that makes any sense? I have to stay stable for my child as much as is possible but I hate that my child see's a fat mum as it's not a good example to set. I've tired "diets" and going to the gym but that gives me a whole new set of problems.