I feel for you having broken my right (dominate hand for me ) wrist and somehow managed to keep on teaching thru the 26 week recovery process. I just plain got good at asking for help - not my usual attitude of I'll do it myself. Then that pebbly shelf liner became my second best friend. I had pieces of it all over the house and classroom. This stuff holds with relatively little pressure, can be wrapped around things that can then be held against you oror pressed against a surface to steady something or wrapped around to enlarge whatever your trying to hold so that it becomes possible to hold more firmly. You can also train yourself to do tasks that hurt with the other hand and in some cases that helps. Example the heavy school doors can be opened with the other hand quite easily and painlessly - just had to learn to reach with my left.
Fast forward fifteen years and a pit bull chewed up my dog and the same right hand. Now I had two broken fingers and three sliced open fingers. Somewhere in the six to eight week range I got so bored I just had to figure our how to sew. I had to learn how to feed the material differently to keep the finger that no longer bends from getting knocked around by the little thing that sticks out and bobs up and down. Then I reverted to to the pebbly shelf liner to enlarge handles etc. Then came cutting and I glued (contact cement some tiny pebbly squares to the under side of my ruler) eventually just used dots of contact cement directly on ruler. Then I invested in some straight handled rotary cutters
where I could put the pressure on it from the palm of the hand. Sewed a bazillion 4 patches == no idea of what I was going to do with them BUT I WAS SEWING. Eventually when you lose the cast you will get a brace and wearing it when doing cutting will ease some of the tiring - even when you are no longer using it everywhere else leave it out in the open in the sewing room. I do this to this day when cutting anything that will take longer than 5 min. And lastly use the smallest ruler possible for the job at hand.