Staci, you're not a bad kitty mom. You just have a cat that loves to eat too much.
I also used to free feed but now I have 2 piggy kitties named Sky and Cirrus so I can't do this any more. I was lucky and caught it in time before they both weighed 20lbs. They only get a few treats on the weekends and sometimes some catsip during the week. They also only eat 1/2 cup of food per day and I feed them 1/4 cup 2 times a day. Now they're more alert and playful too.

Maybe you should talk to your vet about Kylie's weight problem. I know that cats shouldn't lose weight too quickly or this can cause health problems. Good luck and please keep us updated.