OldAussie - Metformin works on what is known as a therapeutic dose basis. What that means is the Metformin builds up in your system over an inexact number of days, so at the outset it can feel like it's not working, and similarly on stopping it, it can take a while to work its way out of the system.
If the Tuesday you refer to is just yesterday, give things time to settle, but whichever is the case, if you are stressing about your numbers going up, the stress can nudge them up on its own.
Take it steady. It's easy for me to say, stay calm and be patient, but I know how challenging patience is at times!