Lots of respect, Moe. You've had a lot of hardship and have gotten through it. If you lost 70 pounds once, you can do it again. Moving from a sedentary job to one that involves standing on your feet will be hard, but it will help with weight loss.
I'll be thinking of you as you start your new job. There's no need to share with people at work, but if at all possible, make friends whom you can talk to. I know that's not easy and it will take time.