I'm sorry for your loss.
As for your weight-loss, maybe you could think of it differently. Instead of calling it "starting over yet again", think of it as "continuing on". Yes, you had an understandable setback, but I prefer to think of setbacks as times when I momentarily got sidetracked and stepped off the trail for a few steps. So just step back on the trail, and continue on in the direction you were going before your Grandmother passed.
Our friend Kaplods, who posts here, has a good analogy. She likens our journey to climbing a tall set of stairs. Just because we fall back one stair, doesn't mean we have to start at the bottom again. Just because we fall back one stair, doesn't mean we should throw ourselves to the bottom! No, we just rest a moment, and then we continue on. Sometimes we lose a stair or two, but that doesn't mean the whole journey has been for naught.
Good luck, and take care!