I've been digitally painting for about a decade or so.
One thing that I have always struggled with is speed painting and gesture drawing.
I've always done some form of art to relax and calm my mind down. But gesture drawing in particular is just something that does the complete opposite. I can't do it for more than 10 minutes before I'm just mentally over it and need to close my note book or photoshop.
Is this just me or does this happen to anyone else? If so how the hell do you deal with it?
(I think you might've submitted this exact post twice by accident, there are two showing up)
Ironically, gesture is the least stressful art exercise for me. I've practiced it far more than any other discipline because most others were just too frustrating! I find it much more forgiving, though some days I can barely do 10 minutes, either.
I'd go back to the basics and do it with pencil or pen on paper. Alternately, maybe set your goal to just paint two or three strokes per 30-second figure. Simplify and focus on flowing through the figure. Be loose and imprecise; the stress will make you want to tense up more but that'll only defeat it. Just go for five minutes a day, and gradually increase that. You're not selling these or anything; they're just to get some energy out and develop yourself a little.
Gesture Drawing is one of the most mentally draining exercises for me as well, especially if you want it done well.
But that's why I do it as much as I can. It challenges me and makes me stronger at drawing so fast. It's something that's done purely as an exercise to help you improve. Just keep doing it and you'll adapt and be able to draw for longer. Keep doing it at 10 minutes. The next week, try 20 minutes. etc.
Because it's so hard, I usually do it at the beginning of my drawing practice session, instead of winding down with it. I also don't go for more than 60 minutes at a time, at most 90 minutes. I'd have to take like a 5 minute break.
Also, I recommend drawing at 2 or 5 minutes per drawing. That's enough time to get basic forms down with correct perspective. If I draw at 30 seconds, I just end up making stick figures with no perspective.