Weight Loss issues.

Since I've managed to separate myself from my addiction to smoking, I thought I ought to start working on the rest of me.  My weight has been out of control for a long time, and after having the baby it's only gotten worse.  Over the past couple of years I've gained about 100 lbs all while taking certain medications.  I balloon up while on them, but once I stop the weight just stays.  I have tried halfheartedly in the past to loose weight, but I'm so scared that committing 100% to anything will just bring back old habits.  I'm trying to do this as best as I can, but it's hard enough on it's own, and I have a baby and a boyfriend to worry about.  He mostly eats junk, so this transition is really hard for me.  I don't know how well I can do with out any support.