I regained more than 50 lbs. in one year so I know how tough it is. I have chronic daily migraines and it's a daily struggle but I sure do feel worse when I"m heavier. I read something here that really resonated with me: If food is not the problem then food is not the solution. I try to remember that but it's hard because when I feel ill and can't workout, it gives me some temporary comfort.
Anyway, my advice is not to think too far in advance. It's amazing how much better I felt after I was on track for a month. My depression was lifted for the most part. Also, keep in mind that you didn't gain all of your weight back. You're twice as far as you were when you first started and you're so much wiser now!
The point is to love yourself and commit to it. Consistency is key. No matter what. If you do slip, jump right back on. Get back on track and stick to your commitment like glue. You absolutely can get back to where you were and it can be done without exercise, btw.