Biking will help build leg muscle and shouldnt make you skinnier. I do sprint triathlons so I do a lot of biking and swimming. The reason they are so good is because they work muscles harder with more resistance and are more of an anaerobic exercise which burns all fat. Jogging burns fat AND muscle. About 75% fat to 25% muscle but you don't want to lose muscle. So if you are looking to keep more muscle you will need to cut down on the long distance running. I have been a basketball player my whole life and our preseason workouts would consist of something like 10x 100 meter sprints under 14 seconds with some 200s and 400s in there. You don't have to cut out the long distance completely but I think you will see that sprints will have you in even better shape. The harder you push yourself the better the results.
I also saw that you said you can only do 30 push ups but you do sets of less than that. You should try doing sets where you go until failure. Your first set go until you can't do any more. Rest then another set and so on. I think you will see better results that way. Keep trying new things.
