Why is my audacity recording so quiet suddenly?

I have been recording before with audacity and had no problem - now today the input level is very low and the track very narrow???
I have Yeti Sherpa Mic and ATR headphones.
Using Windows 10

:cry:

Check in the Device Toolbar that you have the correct (USB) device selected as the recording device.

If that is correct, look in the Windows Sound control panel, “Recording” tab, and ensure that the device is giving a reasonable level when you speak.