I understand you perfectly. For a moment I thought I saw myself in your mirror. I don't have the words or the solution to your problems, because even I don't have the solution to mine.
What I can tell you is that there is a small part of the world that is beautiful. You discovered Swimming and you love it, it makes you feel good, there are other things that are waiting to be discovered by you.
By the way, I don't recommend mixing gym and swimming. I tried it and the wear and tear is too much. The best thing you can do is walk, you stretch and set a goal as far as swim time, even distance, so that you build up an endurance skill and when you have it, you move on to speed. That's going to help you a lot. Supplements the natural. I don't have anything on hand that I can recommend, but food rather than a pill or shake is the best.
Sleep is paramount, if you don't sleep you won't be doing the work you want to do. It will cost you a lot. So your eating and sleeping habits will affect your swimming performance.
As I mentioned, I only swim once a week but went to the gym 5x a week. It was only in the past I mixed both and like you said, it's not that good. Also you're right about sleeping, it is important. I sleep just fine when I swim or during the gym.
I also notice that I spend more energy when I do freestyle than breaststroke. So, I rarely do freestyle especially when I have to get things done. Otherwise, I would sleep the whole day after an hour freestyle session. Thanks for checking out anyway. Have a great weekend ahead.