Getting sober changed literally everything

I don't talk about this much but I was a heavy drinker for years. Like sneaking drinks at work heavy. My kids were scared of me. Anyway I hit a breaking point 18 months ago and went to rehab and haven't drank since. The change has been insane but also hard. I'm actually present now. My memory is coming back. My relationships are healing. But I feel like I lost my best friend and I don't know who I am without alcohol. I'm doing AA and therapy and it's helping but some nights are still really hard. Anyone else been through this?