Some days, you just don’t have it.

You know those runs where you start strong and your stride is long. The air is perfectly crisp and the exact temperature you enjoy running in for long distances. The sun is out and its warmth on your face brings a smile. Your breathing is in perfect rhythm with your step, and your iPod is shuffling your favorite songs in a beautifully timed sequence. You could run all day like this and the emotions you’re feeling helps remind you why you took up the sport of running in the first place.

Some people call that a runner’s high. Some call it euphoria. I call it everything I didn’t have on Saturday.

Some days, you hit that stride and feel strong. Other days, you struggle to find a rhythm and Saturday was one of the latter days for me. I signed up for the Nashville half with plans to run alongside my friend, Beth. While we wanted to run slower, we were still hoping to nab me a PR. This was my third half marathon with the first two being sub-par. The first I ran sick sick with a ruptured ear drum (though I didn’t know that’s what it was at the time) and the second half I didn’t really train for, but decided to run anyway. This one, my third, I hadn’t trained for either, but figured I could hit a PR since my first two half marathons weren’t stellar and my fitness level is strong.

Not only did I miss my PR Saturday, I ran my slowest time of the three races. I couldn’t keep up with Beth past Mile 6, and I walked more than I have in any other race. It was ugly. Three or so miles in, my blood sugar was 300 (I still have no idea where that came from). It came down quickly with a correction and I finished the race at 147.

I don’t know what happened in this race to create such a bad result. Physically, I was fine. I didn’t hurt, and my lungs were strong. But it was a tough race mentally, and I was in my head all day. I haven’t had a run this frustrating since I first started running last year. I thought I was past this struggle with running. I thought I was beyond the doubts and the internal conversations. I thought I was past the rationalizing and the make-it-to-that-tree, make-it-to-that-lightpole bargaining. Two miles in, I doubted whether I would even finish.

It was an off day. Some days you have it, and some days, you just don’t. I kept moving—albeit slowly—and finished with my worst time for the three half marathons I’ve run. As an endurance athlete, I always have a goal even if I don’t speak it out loud. I have one for every race. Saturday, I didn’t come close to finishing strong or hitting my goal, but I still finished. And while disappointed, it’s still another race under my belt. I ran my third half-marathon on World Diabetes Day, and I was able to have a few conversations about type 1 diabetes with runners along the way.

Even though I have goals and it’s hard not to be disappointed when I miss them, I want to remember why I run—and it’s never simply for a PR. It’s for so much more, and it’s why I’ll keep running even if I have a bad day on occasion. (And they still give medals to the slow folks!)