Yes, although you have gained back all the weight you previously lost, the fact that you lost it in the first place shows that you DO have the ability, drive, and motivation to put your health first. And that's awesome! You have done it once, and you will and can do it again.
I personally think walking is a great way to introduce exercise into your plan. A daily walking schedule really goes far! However, it sounds as if you are dreading it. While exercising is something that isn't always particularly fun, it should be most of the time! Maybe you can take along an mp3 player/cd player and listen to music, or walk a dog, or go walking with a friend, or walk in a nice park. Try to change your "routine"once in a while. It will help. Maybe you can also look into some other forms of exercise? Bike riding is very low impact, and is fun too! Whatever you chose to do, make it fun. And congrats on coming back to Spark People. We all fall of the wagon occasionally. You can do it!!!