You don't mention how often you eat. If I have my conversion right you're my weight but a bit taller. When I was training a lot and had a lot of muscle in my legs I was visibly thinner, but the same weight. At that point I could not afford to lose any weight. I don't think you should lose any!

It sounds to me like you're very active, but eat a bit too little, a bit too seldom. "Hungry quite a bit" leapt out at me. Hungry shouldn't catch up - when you're hungry, you need to eat.