Like you said, you dedicated a lot of time to work, now reserve some of that time to talk to your friends too (call the ones that you lost touch but still like).

Is just a matter of focus too, instead of working long hours everyday, take some time to work on your friendships.

To start 1 night a week to call or meet someone really helps, then go from there.

(also I would suggest for you to not drink alone, you could create a rule to only drink if someone is joining you, seriously, don't drink alone.)