I also take Lexapro and know for a fact that stress eating would be a lot more if I wasn't on it. (Just check my Sparkpage if you want to know more about the stress I am dealing with!!) Anyways, blogging is good a way to vent and if you can make yourself follow the nutrition and fitness plans, you'll do just fine!
You've taken the first step and joined SparkPeople! This is a GREAT site! Take advantage of the FREE trackers (nutrition and fitness), the message boards, SparkTeams, recipes, etc. Just start one day at a time. You need to start planning out your meals and decide that you ARE going to exercise and give yourself at least 10 minutes a day of that exercising! There are even FREE videos on the site you can watch...as well as exercises! You came to the right place!!