you have not sunk to any new low at all. In fact I think you've made a big step here in doing something but his saying no is really not unlike what 99% of other people, challenges or not, go through. It's a risk. The part that exaggerates the feeling that it's a new low is that it's not like you're the type to do this all the time so... after having not dated or asked anyone out, etc... and getting a "no" is amplified. Let it make you feel disappointed in the situation and the outcome but not in yourself. You did good in taking the chance.

And as for all those people switching partners like clothing, I wouldn't trade my place with them in a million years. That just means they are shallow enough to take dating as a game and people as throwaway toys. don't compare yourself with them. Some guy will be lucky to get to date you when that happens because you're not one of them.