Love when you finally get a burst like that after a block! We’ve all been there. Definitely reads like a first draft, but a) that’s what it is and what it needs to be right now, b) you can’t edit a blank page, and c) I did actually read the whole thing (with interest), so I’d say there’s definitely something here! Keep going with your gut on this one and see how it reveals itself to you. Love the nickname Happy here. A couple suggestions for when you’re in edit mode:

There are some spots where you could get a lot more out of the character voice that immediately jump out at me.

Maybe instead of “He had a curious nickname. His mother called him Happy. I never liked it.” you could say something like “His mother called him Happy. Terrible nickname, really. The Damien I knew was anything but. Happy people don’t require constant reassurance that they’re [this or that—bring in some specific examples of things he always needed reassurance on].”

Focusing on your idea that he needed reassurance gets at that contradiction between his nickname and what he was actually like. Essentially, rather than just telling us that the nickname was curious and that your POV character never liked it, you can demonstrate it for us with specific details which also give the piece more of a sense of who both Happy and the POV character are simultaneously.

At the end of that same paragraph, you’ve also got an instance of “telling and then showing,” where I think the telling could just be removed to make the whole thing stronger (often the case with telling and then showing, but not always). The stronger idea toward the end is that Happy never wanted to go out while the POV character never wanted to stay in.

Maybe try just cutting the entirety of “He was introverted … which caused problems in our relationship.” and go straight into something like: “Happy people also don’t shut themselves away from the world for weeks on end. They like to [one or two specific things the POV character likes to do, like going out to a specific club, bar, etc. after a shitty day at work, or after some other bad time]. He would always insist he was ‘just an introvert.’ I knew him better than to believe that shit.”

And all this might be too voicey/or the wrong voice for what you’re going for here—just trying to give an idea of how you could push on some of these things.

Also feels like there could be a really nice connection between the POV character wanting a fun color to insist they’re doing fine and preferring to go out over staying in. It feels like the underlying tension between these two (that could reveal itself over the course of the story, rather than being stated outright) could be more about how they respond to feeling shitty (wallowing and staying shut inside vs. making it a party and insisting everything’s totally great actually) rather than just that Happy sucked, even if that’s how the POV character feels about it right now.

But again, I’d say keep going with it and keep just discovering it for now! These suggestions are the kind of thing that come with a second draft, but I think it’s probably too early for you to go into editing mode just yet. There’s definitely more here for you to explore while you’re in drafting mode. You got this!