I'm right behind you, coming up on 18 months myself.
Watching an old drinking buddy get loaded rattled your Beasts cage. So what!?
18 months is awesome. And sitting around getting loaded is super lame. I remember doing it near the end when a good friend came to visit. She had one beer and I had like 12. Nothing cool about that.
I bet a big part of your friend wishes to have what you've got now that you don't drink.