making a plan

I'm recently in recovery for a restrict/purge eating disorder and I want to start a meal plan for myself to get on the right track. I have a hard time eating large amounts at time, (large to me is a whole sandwich)because i immediately feel extreme discomfort, and an unbearable urge to purge. Ive noticed i can eat small amounts like half a sandwich and i don't have the same reaction. I was hoping you could give me some idea on where to start and any other tips you could give me would be very helpful, thank you!
I look forward to hearing from you,
Rachelle