Usually what happens before you reach the point of frustration is you get tense.
This is true for me, and I have had to work hard at learning the signs of tension.
The signs are much the same for most people. Your shoulders come up your elbows move in close to you body, you might even hold or take short breaths. Try to learn to feel the signs of tension and stop playing before you reach frustration!
I take a deep breath let it out slow, and shake my arms down; this helps. Maybe make a video of yourself playing the thing that makes you tense or frustrated, watch this video and look at your own body language; this will also help you recognize the signs.
I even practiced in front of a mirror, I could see the tension happening as it was happening. Obviously just be careful what trick you chose to practice, don’t want to break a mirror; 7 years bad luck. LOL
Hope this helps.