I'm going to recommend to you what I do to brand new members, start with some simple changes. Don't try to do everything at once or you will end up frustrated. Set some simple goals for the week. Example, if you haven't been eating 6-9 servings of fresh fruit and veggies, set a goal to eat 2-3 servings each day for one week. If you're not used to drinking 8 glasses of water, set a goal to drink 2-4 glasses each day for one week. If your doctor says it's okay, take a 30 minute walk each day for one week. Once you've achieved these goals, then you set new ones.
That's how we get our healthy habits back. We don't try to do everything at once. You haven't lost those habits. they're still there. You just need to give yourself some structure by setting some simple goals. Setting goals is a good way to ease you back into your routine.