why do I have no self control when it comes to eating?

Dr
I've been trying to lose some weight and get a flat belly. Well, my belly is pretty much flat but I would like to have some more definition and abs. This morning I ate cereal, my lunch was a salad and one cookie, and my dinner was a small bowl of Mac and cheese. I then ran for 2 miles. But just now as I was laying in bed, I got the sudden urge to eat. I started craving a snack. So I got up and ate 220 calories worth of crackers (yes, I counted) and a cookie. I can't stop myself. I get that I'm still growing or whatever (btw; my period is just ending), but why can't I control myself? I need to stop eating so much. I know I look okay but I just want to be healthy! I drank 3 bottles of water today and this snack ruined my whole plan of being healthy!! Any tips on how to control yourself? I really need help. Thank you xxx