What's it all for?

There's hitting a plateau in your training, and then, there's hitting a brick wall. I once again had trouble sleeping the night before my weekly 3-hour onslaught of martial arts classes, and I made up my mind sometime before I fell asleep for three hours that if I was feeling shitty when I woke up, I wouldn't go. So, I woke up- 3 minutes before my alarm. I felt shitty.
I think it largely stems from a conversation I had with my dad about my frustrations over iai class. The class had nearly doubled over the summer, and now there's hardly enough room to practice. I suspect the presense of Nerverd may also be contributing to my recently negative outlook, but it's not all his fault. I'm frustrated that I've really stopped learning, and that I'm just going through the motions of practicing without actually practicing anything. I had the passing thought that I should skip classes just to break up the rhythm, and to see if anyone actually missed me. So I pulled the covers over my head and slept until one.
I wish I could understand what was wrong with me. I'm far too young to be feeling so damn old, and I always have the fear that I'm wasting my time (not to mention money) on classes. I've only been here a year and I'm in fear of burning out. I wonder if this was how one of our younger sensei felt, the one taking a break. I wonder if he feels any guilt when he misses classes, or maybe he doesn't miss it at all. In that case, I envy him. I hate the fact that finances or my own mental health is eventually going to force me to leave martial arts. But, if I'm not happy with it, why should I care in the first place? What am I doing this for, anyway?