Red Panda and others have made some really important points. These guys are treating you badly because you allow them to and you keep coming back for more. If a guy cancels a date on you, delete his number. Don't respond when he contacts you out of desperation a month later. If a guy says gross sexual things to you, delete his number. Don't go along with it if you don't like it. Don't just let these guys dictate the terms. Decide what you want and, if these guys don't meet those criteria, cut them off. Don't just settle for any old dude that emails you. Set some standards. Don't act desperate. Same thing with the clinginess. Don't reach out over and over when these guys are ignoring you or taking a few days to respond. It makes you seem desperate, and that is not attractive. No one wants what is being shoved in their face. It takes healthy people time to get to know you and decide if they are interested. It's impossible to be too interested right away; you don't know each other! You also don't seem to be at all picky; like any old guy will do. That's why you are sending dozens of these "wanna chat" messages. Be a little pickier about who you contact, and take the time to write something more interesting and personal. I too am someone who automatically deletes every "hey, how are you" kind of message I get online because the person couldn't even be bothered to write something unique or interesting. That's not someone I want to waste my time on. If you want to really spark someone's interest, show them your personality and why you would be a good match for them. Of course, also read about what they are looking for and whether you fit their criteria-- if they are looking of tall blondes and you're a short brunette, you would only be wasting your time.

As for the weight issue, I don't think that is your major issue, by far. However, in general, I do not think it is superficial to desire a healthy, active partner who takes care of their body. I'm not talking "model" thin here, but someone who works out regularly and eats healthy. If I do that, I think it makes sense to want a partner who lives a similar lifestyle. Personally, I want to work out, go on hikes, and do very active things (rock climbing, hang gliding, warrior dash) with my partner. I want to cook meals together. I want someone who takes care of their health so that they will be around and be active in raising our children. I want someone who has a lot of drive, discipline, and energy when it comes to their health, career, relationships, etc. I think it has more to do with comparability and living the kind of life you want than something superficial about appearance.