Eatiing right, exsorsizing and still gaining weight?

I'v been eating healthily and excersizing regularly since october, attempting to flaten out my belly, but it's been afew months and it hasn't changed at all, I eat a bowl of raisen bran for breakfast something light for lunch like a begal, and as well balanced dinner as I can get, I do 200-250 crunches, use my ddr games as a way to bun calories (workout mode counts the calories i burn) and I'm in a karate cl. Why is there no change in how my gut looks? any why do my old cloths from before I gained wait still not fit? if anything they got tighter