I feel ya. There are just some days when it’s not there. In many previous posts we’ve discussed how long it takes some of us to warm up. There are days when I just need an hour or so before I’m really ready to do anything technical or have any endurance, and there are days when I have no skills or endurance, regardless of how long I warm up.
I’m going through something similar to what you’re experiencing learning to juggle. I wanted to do something that would be fun and work out my upper body a bit. I seem to make good progress one day, and then there are days when I almost can’t do it at all.
Yesterday, I was doing very well, but today, I can barely get 2-3 repetitions with the balls, and then they go launching across the room. It’s very frustrating! I thought after three weeks I should be doing better because I somehow managed to juggle three balls on the first day of practice, but today I’m all over the place now. It’s also really tiring to continually bend over and pick up balls up off the floor. That’ll wear you out fast!
At the last juggling club meeting, I was able to juggle for about 2 minutes when I first arrived, and after that it took me two hours before I could juggle again worth a damn. The previous meeting I had done so well that I was passing balls with another person while juggling. It’s even more frustrating in a social setting around masterful jugglers, but everyone is supportive and seems to understand. Apparently, they all go through the same thing.
Both juggling and unicycling require very fine motor skills, visual acuity, and all kinds of complicated stuff. It doesn’t take much to really knock these things off balance (no pun intended). It could be too much coffee, not enough coffee, not enough sleep, subconscious issues about your family, work, etc. Almost anything can upset that fine balance in these early, tenuous days of learning do something requiring this level of skill. Only with repeated practice over the course of weeks and months will you get the point where outside influences will effect you less and less, and even then, there may be days where they will. You just have to push through it and have faith that it will be different the next day. It almost always is. When I’m having a bad day, I just remind myself to feel proud that I even ride a unicycle at all (very few will ever even attempt this) and that I should feel especially proud to keep going on the off days. Even going as far as you have with learning to ride, and even attempting to learn, you’ve done more than less than 1% of the population of the world, and you are already in an elite class of people in that regard. Remember to be proud of that!
What seems to get me back on track during the “bad days” with juggling is just to chill out for a bit and then start from the beginning with one ball, then two balls, and then three balls, and I take lots of breaks when I get tired or frustrated. It doesn’t help me to give up, but it doesn’t help to practice while I’m really frustrated either, so I just take enough breaks to keep from feeling overwhelmed or tired and keep trying.
Maybe on days where it seems you’re not getting anywhere and feel frustrated, you might just take a break for a bit and then sit in the saddle, or pedal around holding onto something and warm up a bit before trying to ride unsupported. Just take as many breaks as you need, get a good night’s rest and hit it again the next day.
Oh, and pierrox, if anyone should apologize for starting a war about the angle of the seat post, it should be me. I was the one that originally mentioned it, so you’re off the hook! 
