I used to get distressed if I was working on something in business or getting into a conversation, and then things just dropped off. I worried that I screwed up or did something wrong. Maybe whoever I was talking to hated me, even?
But no, it's not like that. Nobody hates you. Everyone's just busy, and people you're looking to work with are probably more busy than normal -- after all, you found out about them and want to work with them, meaning they're doing something cool, which makes them more busy than normal.
When you don't get a reply from someone or something falls off, it's usually not because people hate you. They most likely didn't judge you harshly. Probably they just got busy. I've got emails and calls to return from people I really like and know pretty well that I haven't returned yet, because I've got a long list of other stuff to do too. Everyone at least somewhat busy has stuff like that.
That doesn't mean you give yourself a pass on whatever it is -- if you write interesting compelling emails or calls, if you get introduced through someone trusted and well-known, and you can find a way to stand out and make it really interesting right away (not always easy!), then you've got a better shot.
But, even then. People are busy, things drop off. Nobody judged you harshly; nobody even cares. Followup a few more times. Or contact someone else. But don't get down on yourself. People are busy, and you've got to followup with them a bunch to get things done. It's just how things are and is no reflection on you. No reason to feel bad. You just hustle some more.