Re: Should I be eating more?
By "Going back and forth between too much and not enough," I take it you DON;T mean to say BINGE AND PURGE behavior? That's usually a hard nut to crack and pften calls for professional help.
The way to determine if you are eating enough is to look at your weight over time. If it's steady and at a point where you like it and it's a reasonably healthy weight, neither fat nor wraith-thin, then you are consuming the right amount of food.
You might want to tabulate your calories for a week or two and store the info somewhere in case you run into trouble when you're 40.
If however, you've been slowly gaining over the last couple years, then you might be eating too much and want to cut back.
Vice versa if you've been losing more weight than you like!