I clench my fists too...when I wore braces it helped.

I think a strap for your Ipad would be an excellent idea...

Also, during the day, do some exercises. stretch your fingers, then bend the fingers down to the second joint. Next bend the fingers all the way into the hand. then straighten them again.
Also get some of that putty that PTs use, or a stress ball and squeeze. It helps loosen up the muscles and ligaments in the hands.

Sorry you're feeling poorly, dear friend