Lozz, start increasing your calories - at least a 100 per day, I'd aim for 300 per day extra. At that rate you won't be adding weight fast, you can get used to the extra food. Add nuts, cheeses or other higher calorie foods, they are the easiest to add calories with. Keep your protein high and you should be able to regain some muscle as well as fat, though you will put some fat on, but you need it, so don't be afraid of it.

I know it's hard, but try to stop worrying about your stomach. You can control what you put in your mouth, but you can't control what your body does. It's possible you could lose another 10 lbs and still have the stomach, we can't tell our bodies where to take the weight from. But if you regain some weight, likely you will regain it in the places that look emaciated now.

If you are worried about the skinny-fat thing, start doing a little exercise, but not too much (if that was an issue for you before), if you are eating enough and weight training, you should build muscle and I think you'd be very happy with that result.

Val