People in this thread have made good suggestions about how you can be a tad more honest while also keeping things brief and polite. I found this surprisingly effective in making me feel less hollow, but something that really helped me was having friends who I could be completely honest with when they asked how I was doing.

You might not have friends like that. Certainly, I have found that when I’m tired and depressed is when I am most distant from would-be friends, and there have been times when I have effectively had to build up a support network from scratch (which is especially difficult when depressed). Or you may have friends who you hold at arm’s length because you don’t want to burden them with how you’re feeling. I may be projecting here, but when I have been depressed in the past, I end up feeling like I’m almost “infectious”, and I end up withdrawing. If you relate to this at all, try to resist the instinct to isolate. Try your best to put yourself in situations where you could meet people, such as if any hobbies you have had (or considered) have a social component to them. If you’re starting from nothing (which I’m assuming you are, given your aforementioned loneliness), a large chunk of forcing yourself to engage with things will feel like a chore, but in my experience, that’s the only way out (ideally paired with professional support, if available)

“Anyone else here feel like that? If so, how do y’all cope?”

My honest answer to that is either “I don’t know if I am coping”, or “solidarity”. My above response may sound like I’m relatively coping, but in many ways I’m not. The times when I feel like I’m most achieving what I need to in life are often the times I feel most exhausted. In a way, it would be nice if I could think of myself as struggling due to some innate brokenness, but there are so many people struggling in the same way we are that it’s abundantly clear that our material conditions are the problem. It’s depressing to see how many people feel the same as I do. But it doesn’t make me feel less alone, and that feeling is something I cling to. It’s something, at least.