Blood sugar / glucose monitor?

holy frijole man! I read you are supposed to go to the ER when over 240.
I saw 340 after I was prescribed budesonide and panicked.
Lately I noticed eating a lot of meat, drinking much water and brisk walking keeps the number lower. Managing to stay in the pre-diabetes zone or near it and that is while taking prednisone. I don't want more medications, especially shots.
240 ain’t nothing. Thats like turning your SB 4000 RPM. Most meters will read to 300-400 then the meter will say Hi. Most diabetics are lucky to keep theirs between 100-200.