How much weight and calorie intake should I do regularly?

Ok so I'm not fat but I'm getting warnings from my body because low and behold, my blue jeans that I regularly fit into got tighter and if they get tight then I know I have gained some weight. I am a male. 18 years old and I weigh 165 pounds and I am 5'8 and a half. I believe that I am still growing till the age of 22. But I am doing 100 push ups and situps a day and I do 20 each then I take a short breather. I would like to know how much I have to do to get in shape and what types of food and my daily calories I should take in. Thank you.