How can I get a flat stomach quickly?

I am an athletic junior in high school. Last summer I had a fairly flat stomach but then i got injured this fall and had knee surgery. This forced me to stop doing sports but I still ate the same. I seemed to have gained weight. Because I am short for my age (under 5 ft) there is no way to hide this fat. I am beginning to feel self conscious and I am going on vacation in 3 days. Is there anyway I could get a flat stomach that quickly? also how can I get a flat stomach in the long run? PS- I have been cleared to work out by my surgeon.
How should I eat?
How should I work out? should I run? cardio? abbs?
PS- I do not have a gym mebership but I live in a big city right along the lake
THANKS

Wondering How To Lose Weight Quick?

Recommended Answer:
Maybe you could replace meals with shakes full of protein, there r some recipes out there that mix spinach, banana and things like that. Try not to eat out too much cuz you really dont control what youre eating. Eat more salads, because I became a vegetarian,but for personal reasons, im not saying u should do that, I lost a lot of my belly weight, it is incredible because I always had the meat and in my hips too...I now drink more shakes, eat a lot more vegetables, tofu, soups...and i dont even work out, and my stomach also kind of reduced because i skipped breakfast and only drank coffee, but thats bad, i eat cornflakes and banana now... so do the research, replace foods with healthy ones and workout and u will get there. Get a juicer too....

• There are certain Ab Exercises which helps in makings your Ab flat. You can search those on YouTube. You can also buy good Ab Exerciser available on health equipment stores.