I also posted on this site when I had 39 days. I’m now just over 100 days so I’m no expert by a long shot, but it sounds like we are on a similar timeline.
The first 30 days were not so bad for me as the reasons I quit were fresh in my mind and the physical withdrawal was a painful reminder for me to not drink. After the newness of sobriety wore off I was left with my own thoughts and sober self which I had not had to deal with for a long time. Between 30 and 60 days was probably the most difficult period, and I almost caved multiple times.
Finally around or just after the 60 day mark I had my first “good” day where I was genuinely happy...maybe natural endorphins finally being at a normal level.
By the 90 day mark the good days were starting to become more and more frequent and I felt 80-90% back to my old self before alcohol had become a part of who I was. I now feel clear headed and even keeled.
The key for me was listening to people on SR who had achieved long term sobriety and understanding the negative feelings and cravings will eventually go away as long as you never take that first drink. There are a lot of wise and kind people on this site that I am grateful for.
Some days early on my biggest success for the day was not drinking, and I went to sleep angry that I couldn’t have a drink. But not once did I ever wake up the next day saying...man I wish I drank last night. Similarly I have yet to read a relapse thread with someone saying they were glad they took that first drink after a period of sobriety.
39 days is awesome!! You can do it! One day at a time.