Swimming workout question?

Hi, i am 19, male, using someone elses account, anyways my question i been swimming for a few months and i got pretty good so i want to make my workout more challenging, to tone down, lose weight and get better, anyways the workout will consist of swiming 10 full laps, 500 yard, front full crawl motion, speed medium to high, everytime i complete the 500 yards i get out of the pool quick do 20 pushups and repeat, this would go on till i do it like 10 times, 5000 yards 200 pushups , a 3 hour long workout or more i need to increase my speed as well, thank you.