Benny, I'd like to offer you an objective analysis because I believe you're in need of someone with an objective perspective. I'm doing this because I care about anybody in need, but I'm having a pretty hard time right now, depression-wise, so please don't take my blunt analysis as disrespect....
I believe he's long-since decided that he's better-off without you in his life. It doesn't really mean you did something wrong: the universe comes together in terms of compatibility.
He only texted (and thereby acknowledged) you that one time, but not every action has a significant depth of meaning: it was most likely a passing moment of "what the heck", where he sent you what he saw as a polite-but-meaningless text.
When people really, genuinely want you to join them, they say "come join us." When they're only saying it to be polite & avoid conflict, they say "you can join us if you want."
It's a subtle way of saying "I don't want you to join me, but I'm too polite to flat-out say 'no'."
I completely understand where you're coming from (I've been there myself in younger days). But the signs seem very clear... bright & glowing, in fact. A friendship is not in the cards.
Personally, I've found that the most important thing to my mental health is a conscious decision: to put your mental health & well-being as a priority above all the rest. Finding inner-peace will never be a matter of satisfying the hard-wired program in your brain that craves an impossible return to old times.
Happiness is in accepting the flow of life: learning to create new experiences, new emotions, the changes that you'll never see coming at the start - instead of clinging to that who's time has passed.
One does not search for new sources of happiness by knowing what to seek out. One sets out on creating new paths, walking them and finding out where they lead.
Hmmm... my Taoism studies came back to mind. lol
I hope this gives you something to think about, maybe even help.
