WHO IS this woman and WHERE did she go??

I had the funkiest running week. I have always LOVED running. What happend???!!!?? Somewhere in there I woke up and just didn't want to go. Just wanted to sleep in. Then had to like MAKE myself get my 18 miler arranged (don't like to be in the canyon by myself for that far at that time alone). Vanessa and Lori went with me---we are all at different paces, but we at least knew we'd be somewhere close to each other on the trail. We started out at an 8 mile pace...too fast for me to maintain, but felt good for a few miles...this is poor Lori's first time going this far and she is running about an 11 minute pace. I'm at 9:30 and who knows how dang fast Vanessa is...8:30?? By mile 5 we have separated and Vanessa is flitting back and forth between the two of us running ahead and then behind getting tons of extra mileage. When I say "flitting"--I mean like a GRACEFUL GAZELLE...it was truly something to watch. She just kind of danced down the trail making it look so EASY and FUN. That use to be me. I wasn't feeling it. I felt DONE. My head started trash talking me and by the time I was at about 12 I was totally mystified as to HOW I had EVER run marathons before?? 18 miles is so freaking long!?! WHO and WHY would ANYONE ever even consider such a ludicris thing? I even went through the whole "I must not have eaten enough, do I need more water? Have I HIT the WALL?" but no...my BODY still felt FINE...I finished the run, went to Rapier's pool, then got in our hot tub, then spent the day working pretty physically helping the Bean's lay their new paver patio...and the feeling still hasn't left. It's the morning after and I don't have any aches or pains...just this huge void in running love. Seriously...what the heck IS THIS?? And WHY HAVE I felt the desire to be so extreme?
To top it all off...Don comes home from the bike ride of his life having taken MY IPOD and listened to Norman Vincent Peale "You are what you think" and then tells me how much further and harder and better he was able to go while listening to such an inspiring and hope filling talk.
I know that stuff. What happend to me? Why is it still gone...how do I get BACK to WANTING to love it...a little scared this morning after. Truly even wondering WHY I signed up for the marathon and IF I'll run it. I mean I will run it cause I paid the money and if I didn't I'd feel ...WHAT WOULD I FEEL???? Geeeezzzzzzz.....