Wow! What a weird and horrible sensor I had ended up using since Monday (4-15-19). That sensor had to be replaced today because it failed on its own this morning after I was on the computer and phone. Right now, I'm waiting on the warm-up period to be done so I can calibrate the sensor that I put in after getting off the phone earlier.
The old sensor that had failed was causing so many problems since Friday during the day and even before going to bed. The way it went goes like this: give a number for a few seconds then goes away for 1-2 hours with nothing; give a number then ask to be recalibrated, but doesn't allow the calibration to be entered; shows question marks and hourglass with and without a blood drop icon; gives a number and it's 300+ off! This was how things have been going ever since Friday. I was woken up this morning around 2 am and was told that my number was 188 with two arrows straight down-- not true. I tested myself and was actually 277, but couldn't do anything about it because you can't calibrate with straight up or down arrows.
The new sensor I asked for will be here in a few days this coming week.
Lunch time here.