metronome in recording

Hi, I’m new to Cubase and recording in general. I’m using Cubase AI8 with Windows 10 on a Lenovo laptop. Whenever I record with the microphone while using the metronome, the metronome sound can be heard in the recorded track. I believe the click track output is being routed back into the input bus. To test my theory, I played an MP3 while recording. The MP3 could be heard on the recorded track. Both the click and the MP3 can only be heard in the recording when there is input to the microphone. For instance, if I start recording and am silent for the first measure and begin playing on the second measure, the background sounds (click or mp3) can only be heard when the music starts on the second measure.
I’ve disabled stereo mix and the laptop microphone but it didn’t make any difference. I’m using sound reducing headphones as a monitor and the click sound is not bleeding over into the microphone. Has anyone had a similar problem? Thanks for your help.


What Audio Device do you use, please?