You’ve become boring.
Sorry to give you the most cliché answer available but it’s probably true. When was the last time you tried something new? Joined a club, took up a hobby, asked someone out on a date or learned a new language? You are bored because you keep saying, “Nah”, to the things you should be saying, “Fuck yes!”, to and now you have nothing to talk about when you go on first dates so nobody ever calls you back. Surprise, surprise.
The most important thing is to do stuff; anything is better than nothing. If it’s not working for you, change the things you’re doing and try something new.