<human>: I don't know how to explain this. Life feels like misery. I hate it. The only thing that matters, the only time I'm ever really alive, is when I'm crushing on a girl and she's returning those vibes. It's like you eat something so delicious that everything else tastes like sand.

It started when I met my first significant girlfriend. We spent every waking moment together the first month together, and everything else was just in the way. When that relationship eventually ended, I tried to fill the void with a bunch of casual sex. I eventually met another girl I liked, and fell into the same pattern. That was nearly a year ago. Recently, I met a girl I really liked with the intention of doing a casual thing for the summer. There was this initial spark where she kept asking me to spend time with her and was showing me off to her friends, and it's like I couldn't fucking help myself; even holding myself back on a surface level by giving her space, it became another goddamn obsession. I don't even know how to describe it because it's barely even about her. And now she's cool towards me, but I'm all wired and fucking depressed because I can't get my fix.

What the fuck is wrong with me? It isn't like I don't have hobbies, or aspirations, or friends, or habits like exercising, but it's like none of it matters. I can't tell if it's an issue like addiction or if I have some underlying issue(s) that I can't even begin to see. I know I have low self esteem. I don't make enough money for therapy. It's not like there's some magic hobby out there that's going to somehow replace this.

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: crushing on a girl and her returning those vibes is like heroin and the rest of my life feels like I'm just waiting for another fix. It's like I'm not alive unless I have someone to focus on.