If you can't eat 3 meals a day, you need to change that, regardless of how hungry you feel and how you're used to it right now. It could screw up your growth and can also cause problems like moodiness, cramps and even depression.
I bet you'd know how to do it - just eat 3 times a day!
When you wake up, eat a meal, or as much as you'd like (but it has to be SOMETHING). Then do it at lunch, and at dinner etc. It's a habit that's hard to get into once you're out of it.
Are you online a lot? Do you watch a lot of TV or do something that doesn't make you move around a lot of hours? That's the main reason why a lot of people lose their appetite, stay up until 4 o'clock+ and get depressed. So yeah, I think you should really start eating 3 meals a day and maybe even get active (if you're not already) =]