I know how grief can knock you down.I lost my own mother about six years ago.
And it did contribute to my bad eating habits for awhile.
But the pain does lessen over time,and you can remember the warmth of love they gave you.
I would suggest that you do a search for a grief support group in your area.That's what they're there for.
Also you might consider joining something like Weightwatchers, or a Gym,or fitness club of some kind.The best way to meet new friends in the area is to go for what interests you.Hopefully you will meet some like minded people.