That is so weird Allison. It almost like someone who goes on a cocaine bender (drugs release endorphins) and then comes crashing down afterwards! I am NOT comparing you to someone who uses of course, but it almost sounds like your endorphins took a nosedive, leaving you feeling wiped out from the physical activity, and depressed because the incredible high is gone. Wow, isn't that nuts?
The good thing is you obviously can get it going again, but only after you rest your weary self, eat well and feel ready. I am in awe of you, attacking this challenge and completing it!:7