Analogue readings reduce when widget is connected

I have a simple program that reads A0 from a thermistor (TMP 36). I convert it to volts and Celsius and update V0 and V1. This part works fine.

If I then add a widget to read the A0, the reading drops by a factor of 10; thus my temperature and voltage readings on V0 and V1 drop as well.

Is this a bug or is it just a bad idea to attach a widget to an analogue input that is already being read as part of the program?