You say you've exhausted everything and that you take care of yourself and your appearance, but are you doing it because it makes YOU feel good or are you doing it in the hope that it will attract someone to you? I find that sexy is all a matter of perception.
For example, if I'm at the gym and I see a guy look at me, I could choose to think "oh, I happen to be in his sight-line and he's not really checking me out" or I could think "that guy is completely staring AT ME". Now, I'm not going to talk to said guy, and said guy probably won't talk to me, but I certainly feel better thinking "he is checking me out (and why shouldn't he - I'm hot") versus "I just happen to be standing where he's looking." This is kind of an extreme example, but I hope you get what I'm trying to say. Your ability to feel attractive shouldn't depend on whether you have a guy in your life lavishing compliments on you. It should come from the knowledge that you are a beautiful person on the inside and on the outside.
Now as for the list. You've really done EVERYTHING? Climbed Everest, walked a volcano in Hawaii, been to Machu Picchu, visited the Pyramids in Egypt, learned French, slept in a castle in Scotland, cooked 10 new recipes, invented a new kind of cookie, called 5 people you admire to tell them why you do, spent time with nieces & nephews, hosted a party for no reason other tha to just spend time with friends, paid for the person in line behind you at a coffee shop, etc., etc., etc.? I'm going to hazard a guess that perhaps the reason you are feeling so low is that you've stopped dreaming. Your sole focus has become to get a guy and everything else (apart from what you have to do on a day-to-day basis) has fallen by the wayside.
The examples above are from my own list. I don't have the resources currently to go jet-setting off on a global world tour to check all these off, but if I focus on the things I want to do, I'll get there a lot faster. Having dreams and goals is vital. If you only focus on one, of course you'll end up disappointed when it doesn't happen but if you have 10-12, or even 150, you not only live a rich creative life but you create so many more opportunities for good things to come into it. If you are having trouble coming up with ideas, I recommend looking up the Day Zero project online. They have "would you rather" lists with a ton of ideas to try; i.e. would you rather learn french or go sky diving, would you rather learn to make brownies from scratch or learn to sew a skirt - you get the idea.
Stop punishing yourself by trying to be something that you THINK guys want instead of being the awesome person that you are. Get involved in things that make you happy, spend time with your daughter doing things on your New Moon List, find out what kinds of things she dreams of doing and do them together. Make some time for yourself. Write down the characteristics you want in your new guy, then put it aside, and forget about it. Focus on other things, make yourself happy. Funks are terrible and they are hard to get yourself out of, but start by focusing on what is positive in your life. You have an amazing kid, you are raising her on your own, you are taking care of your body, you are able to afford clothes to look good in, etc., etc. etc.
Best of luck,