My first thought is that you're just not eating enough when you do eat, but without knowing your height, weight, gender, age and total daily food consumption, any guesses would really be a shot in the dark.
I have only recently gotten to where I can push my first meal out to 11am and I do notice that what I eat then affects how comfortable I am waiting until dinner time to eat again. 300-400 calories of plain (sweet or white) potato works best for me. A mix of meat (lean or not) and veggies takes *at least* 500 calories to hold me. Obviously if weight loss wasn't part of my plan, how much I ate at lunch wouldn't be any big deal.
I'm jealous you slipped into IF so easily. If it were me, I'd try waiting til 1pm or so to break fast as well. It's hard to know what will work til you try it.
CW-125, part calorie counting, part transition to primal
GW- Goals are no longer weight-related