Sober life is as boring or not enjoyable as you make it.
It does get easier but it takes time.
To get rid of your weight gain, and alleviate depression/mood swings get into exercise even if it's just taking a walk daily.
Some people find getting into a support group like NA/AA, or another group to be helpful but they get a sponsor and take sobriety seriously.
Since I got sober about 3 years ago I've gotten more into gardening, cooking, reading, writing, and I keep busy aside from work, and make sure that no matter how bad it gets I don't use alcohol or other drugs or hang around with friends I used a lot with in the past in places we used like in bars.
Don't feel bad about relapsing it's not a mistake if you learn something from it.