It's normal at your age to think about other girls and to even think about sex a lot. I think it's good you're taking a break with your GF because it's not fair to her, when you're all confused. I think you need some time to think and don't concentrate on having any girl for now. Just be friends with people for now. No you shouldn't be mad at her about the banquet - it would be awkward for her to go with you, considering you're supposed to be apart. Try to relax and it's normal to feel bad since you just broke up. Give yourself some time to think but try not to over analyze things.