OP, I am going to be brutally honest. You come across as very needy, and I think men can sense it. I can sense it, the neediness is oozing from your messages. I know I sound so harsh but you asked for advice, and I can feel it in you because I used to be like it too. I used to be over invested quickly, I used do accept breadcrumbs, I had poor boundaries, I'd put men on a pedestal after hardly knowing them etc etc etc. Neediness is very off putting (this works the other way around too by the way, needy men are off putting too).
You need to figure out what the neediness is about but I think the first step is to figure out what you actually want. What kind of man are you looking for ie what are his qualities, values etc. Your posts sound like you're not quite sure what you actually want, and any man who gives you a bit of attention is put on a pedestal and you start desperately waiting for him to get in touch/to want more, when realistically you don't know anything about this man. And honestly did you even enjoy their company that much or is like a PP said a sort of limerence type obsessiveness, and is it actually about these particular men or more about your neediness to be with any man? (Not any man but you know what I mean I think).
Once you've figured out what you want from a man, only date men who fit your criteria. I am not talking about ridiculous unrealistic things like he has to have a certain nose, height, hair, specific job etc but things like he has to be emotionally available, be into me and show it, be kind, treat me well, be consistent, be ambitious, be in a caring profession or whatever it is that is important to you. So when you actually meet someone and their actions don't go with what you're looking for, move on. So someone like that guy who only wanted to be friends would probably be binned instantly (instead of you accepting crap from him) because you'd have realised 'wait a minute, his actions are crap, he's stringing me along or probably keeping me keen while waiting for someone better to come along, and that's not good enough for me'...
I have lots more thoughts and advice but feel like I'm being a bit cruel/too brutally honest. So before I say more, please let me know whether you find this brutally honest advice helpful at all. Do you know what you are looking for in a man? Is this something you've thought about before or could start thinking about?