I was a strict vegetarian for 10 years and then started training really hard as well. Not only was I so hungry, I also started losing hair from the front of my hairline. Since I ate dairy, I tried to up my protein intake there through cottage cheese, Greek yogurt, low-fat cheese and ended up gaining belly fat. Since I am vegetarian primarily for health reasons, I decided I had to adjust.
I started eating fish (mostly tuna and salmon) and cut out the dairy, except for occasional treats. I also eat a lot of eggs and one protein smoothie a day. It made a big difference in how I feel and I saw my hairline coming back within about 6 weeks. And even though I usually eat 2 egg yolks a day, in addition to more whites, my total cholesterol is its lowest ever at 155.
I make sure I eat protein with every meal and snack, like apples and walnuts, banana and peanut butter, veggies and hummus, and that helps keep my blood sugar and energy levels steady. Everybody is different, but this is what worked for me. Even if you don't want to add fish, you may want to really focus on upping your protein through nuts, seeds, hemp powder, tofu, soy products, etc.