It's not easy WBF, trust me. I have my Lyme friends and that's about it. Everyone is drinking as long as they can. Or getting high. At my age they don't have responsibilities or declining health preventing them from doing otherwise.
Your feelings are totally normal and understandable. I went down at 26 and was at the prime of my life career-wise and partying-wise. It came to an abrupt end and I always had the itch that I never got it out of my system. Doing things with people of your age is normal and a right of passage. It makes sense that you long for it.
You'll have it. And when you do you'll be bringing a more appreciative, jovial aspect to it that your friends never did because they never lost it. You'll also have other priorities in order that they don't because you spent time forced to concentrate on other things. You've been able to observe things from the outside and when you're able, will reintegrate with a more coherent vision of where you're headed and what's important. They won't have that.
That and whiskey. You'll have lots of whiskey.