My 2nd year of competitive swimming, a few questions

Hello everyone, just joined this forum a few minutes ago. Glad to be here! :) This will be my second year of competitive swimming. I swim for my high school which is one of the top athletic school in the country. Our team has a rigorous swim season and every athlete must be devoted or else they are kicked from the team and / or do not swim in any "top" or potentially any meets. I have been swimming for 13 years(I am 17), however last year was my first year of competitive swimming. My times were only miliseconds off state records and I think this is my one of my talents and something I am almost born with. I have a few questions about off-season training since I have been training every single day this summer for the upcoming season in November. Also, starting in April I have been lifting weights at the gym for 2-4 hours a day. I was getting pretty "big" so I stopped and now for the last 2 weeks I have been swimming.... 6-7 times a week. 1. I swim 2 hours every day -- I lose track of laps and possibly do around 100+ a day. Only problem is I do not have a routine I follow. I just dive into the water and do what I feel like. Can someone help me pick a nice 2 hour routine that involves every stroke? 2. Since I have stopped lifting at the gym, should I cancel my membership? I've been reading a lot about how "dry land / gym" training is excellent for swimmers, but why can I not become a better swimmer just by swimming? I thought practice makes perfect, no? So should I keep this gym membership? 3. How can I increase my stamina on every stroke? I am a fast swimmer but I burn out pretty quick, I cannot do anything 200m or higher without a rest, and that is why I do not swim the 20-lap free in competitions. Thanks!