How do I control my urges to eat?

And how do I learn to be satisfied with normal serving sizes?

I try so hard and it works for me for a little while. but sooner or later, the thoughts start creeping back in. I just love to eat. I would eat when I am bored and there is nothing else to do... sometimes when not even hungry I would eat just because I felt it was too long since the last time I ate! I try not to do that now, but the thought of eating starts to, well, eat, at my brain. I also seem to never be satisfied with the right portion sizes. I've spent so many years eating more than I should, I am struggling with the transition of eating the amount that I should. I will portion out exactly what I should be eating, but an hour or so later, I do and serve myself half a portion size again because I am hungry and sometimes even later, I'll do the same thing again. Because I've been doing this again, I've noticed my weight loss has slowed down a lot and I am just afraid I might fall off the bandwagon without some advice/tips/support/ whatever. Help me fight this addiction!