Good workout needed!

I am not overweight at all, but my stomach has been getting a little chubby lately. I play sports and I’m facing hard competition for varsity next year. I really need to get in better shape. I used to have abs but those abs have disappeared this year. I really want to get them back. I have already changed my diet but I need a good hard workout to really improve my health. Does anyone have a suggestion? (I don’t have access to a gym at the moment, but I have weights at home and some workout equipment). Please help!