My longest run ever and so much pain

So, many of you - I am sure have experienced this feeling. You are running - you are on a long run (or maybe sometimes a shorter run), and all of a sudden - your entire body hurts from waist down. Maybe it starts in the front of your knees, or in your hamstrings, or maybe if you are really having a good day, such as I had on Saturday, it will start in your lower back.

My great friends (and amazing trail marathon runners) drove down from Asheville to accompany me on my first 15 mile trail run. They were patient (I was already feeling tired), and we embarked to run ALL three trails at one time. Although some of you may be wondering how I reached the sum of 15 miles from the earlier description - you have to run on the road some to access Ladyslipper & Sourwood and then run some to access Lake Russell. With that rough quantitative analysis completed, I will proceed to the qualitative description of my body's decline around mile 13.

We were doing well; I had slowed down; we were finishing the run on the Lake Russell trail; we had just completed the Ladyslipper trail, so we were tired from doing much climbing, but we were still running - when all of a sudden my knees started having shooting pains, my hamstrings tightened which spread to my lower back, and I was stopped short and thrown over - I felt as though I was going to break in two. I was in so much pain; pain I had not ever experienced before. Immediately, my mind started racing - I have run many miles and for many years(since I was 14) without injury. I am not prone to injury; however, on Saturday, I felt as though my whole body had a meeting without consulting my mind and decided to shut down. I stopped running; I walked. While these thoughts were racing through my head, my companions reminded me that my body was not used to this distance, that these feelings were normal, that each subsequent run will be easier, but I just stood there. How could I feel this much pain just from running? An activity I have done for over 16 years; I love to run; my joints don't mind; my knees usually don't mind. And yet, and yet on Saturday morning - all my assumptions had been shattered. I cannot think of analogy to help depict the image of me bent over trying to fight the pain - Wonder woman becoming human? A person becoming a zombie? (a little extreme...)

How am I supposed to run 11 more? (11.2?) Oh yeah, it gets easier...