It’s only human to be upset with that situation. It hurts. How could it not?
Coming out of your shell and taking an interest in people will always be a prerequisite part of it. Nothing happens without that. Don’t feel bad for having done that. It’s a big step you should value in yourself for being able to do, some people can’t do it at all. It’s something you will need and I’m sure it wasn’t easy to do.
The other important part of it tho, is the hard reality that most people won’t be interested in building a connection. This is true for everyone, from the most popular to the least. Most interactions just don’t really end with any real connection. While it’s undoubtedly easier for some, it’s never some large fraction. Most interactions are shallow, bonds tepid, or superficial, the real true connections are always the very rare commodity nestled in between amongst all that.
So I think the only thing I can tell you is, it hurts much less when throwing the dart expecting to miss the mark, rather than to succeed. Because that will be the actual reality most of the time. It’s the desire itself behind the most pain. But there really is no shortcut, have to keep throwing that dart to hit anything, or to learn new things in the process.