I'm having extreme stomach cramps, could it be that I have not eaten a lot today?

I've been really emotionally tired and depressed the past 3 days or so, and my appetite has dramatically decreased. All of my friends are used to me being hungry every second of the day, so it's odd for me when I'm not eating a lot. On thursday I was still eating, but in smaller portions and I had small bowl of organic cereal that doesn't really have any sugar in it, I had an arizona iced tea in the flavor watermelon, two small pieces of pizza, and half of a jack and the box toaster sandwhich. On Friday I had even less, hald of a wheat sandwich with two pieces of salami, a piece of cheese and a little mustard on it, then I had about 10 cheezits and later a little over half of a burrito sort of the same size as chipotles. Today I had a half of a bagel, some pineapple/orange banana juice diluted with water, 4 cheezits and this evening I had two small pieces of pizza and two caprisuns. I even passed up on the cake! I'm a little worried, I have been wanting to not eat as much and be healthier, but this isn't the way I wanted to do it. I feel like I'll get sick if I eat anything, and I just have no appetite. Right now I'm having really bad stomach cramps and it's making me nervous. They are kind of in my sternum area down to the middle of my waist, and my left side. I was 146 at the begining of the week, then I measured myself on thursday and I was 145ish. right now, it's the evening and I'm 142. I'm 5'8.5/5'9. I'm having some back problems right now if that could have any part to do with it? I'm having a problem like scoliosis but it developed only about 4 weeks ago, so we think it was from an injury if that helps. It took off about 2 inches of my height. I'm 14 years old, 15 in a few months. Please give me any advice or info on what's wrong with me. :/I'm having extreme stomach cramps, could it be that I have not eaten a lot today?
you have your body in shock if you just started to eat less. and also eating unhealty isn't the way to go. you need to rethink your diet plan.