Well, this is very disappointing and got me stressed out for no good reason last night before heading to bed, but since the sensor from Monday afternoon wasn't behaving on and off during the day, I finally had to take it out and insert a new sensor before falling asleep. This means, I had to stop the sensor from Monday and wait the 15 minutes before inserting the one that I'm using now. After inserting the new sensor, I called to get another free sensor sent out to me. That new one is coming sometime next week. The other free sensor from last week has been moved to arriving tomorrow ( Friday) sometime before 8 pm/end of day. I hope both free new sensors aren't too late arriving since I may need a new one hopefully when the correct day is going to be scheduled and I won't have to worry about the amount that are left waiting.
When the 2 hour warm up period ended, I was so tired I didn't even hear the beep from the receiver going off because I was sound asleep. By the time I saw what the new sensor had done, it was close to 3 am ( I had to get up to reposition myself). So, when I got up, I went to check how the warm up had gone and if there were any readings. Turned out, the warm up had passed and I was in the low 200's with a straight arrow going sideways. After all that was done, I got back into bed and went back to sleep until close to 6:30 or 7 am.
The new sensor is doing great so far today and I plan to keep a very close eye on it to make sure nothing goes wrong this week into the next upcoming 10 days. I'm hoping it'll last the full 10 days. Will see what happens soon. Watch this spot for updates! 
