In need of support

My name is Jennifer.I am 46.I have usually maintained a healthy weight until I got sick (ear infections,anxiety,vertigo,dizziness etc.)that left me bedridden because I was too dizzy to walk.So I have been leading a sedentary life where I was once busy and on the go.I used to avoid "bad foods" as I knew I could never exercise them off.But within the last year that changed and I have been eating 1-2 bags of chips/day and handfuls of chocolate(I suffer from depression and this is my new comfort food).In 6 months I have gained another 30 lbs. Before I got ill (back in 2001) I was 135lbs .Yesterday I weighed myself and I was 240!! I have a 20 month old grandson who I can't play with because I am either too tired or out of breath.I am long overdue for a BIG POSITIVE change.My goal is to drop 100 lbs in 10 months. My concern is if I start to feel hungry or shaky, I will blow my whole diet. Tips,suggestions and support would be greatly appreciated. I don't belong in this body anymore,it's unhealthy and it's tired!