I don't know how big a sandwich plate is but it doesn't sound like you eat that much. Of course, I don't know the kinds of things you eat. Do you eat enough protein? That's what will keep you full. And you get hungry enough to feel sick after 2-4 hours? Are you on a diet right now? Because you could be feeling like that because you're eating too little...
If you can use a website like my fitness pal or sparkpeople. On those websites you can track the calories in macronutrients in everything you eat and they will tell you how much to eat depending on your weight, height and activity level, although they tend to allow you too many calories. Most of those sites are free and they help a lot. You'll also find articles, etc, there where you can get a lot of information. You should look into it.
In any case, I don't think the meeting would hurt you. I'd thought about going to overeaters anonymous, too, but I moved away from the town where the meetings were held. It could help you.