Well I can tell you that the lethargy does pass…it just seems like it takes forever. I was the same way the first like 2-3 months. I remember feeling very frustrated because I finally was doing everything right and I still felt like crap. You just have to let things run their course. Years of downing alcohol definitely takes its toll on the body and it can take a while for all the toxins to work their way out of the body.
Perhaps doing some research on how alcohol physically effects the body will help you stay strong through early sobriety. Also, there are lots of resources (other than AA) to check out. Smart Recovery, Women for Sobriety, etc. There are tons of resources on this thread:
There are also things you can do at home to keep you on track. This one is my favorite:
https://talkingsober.com/t/great-article-on-how-to-set-up-your-plan-relapse-prevention/5913
Stay strong! Keep checking in! You can do this!