I'm not sure what happened, but I'm stuck in zoom tool. The odd part is: The cursor displays itself as a square (or diamond shaped) magnifying glass. I can't select any other tool, trying to draw a line does nothing, and worst of all is that it seems to be permanently stuck. I've tried restarting, restoring defaults in settings, re-downloading, completely erasing and then re-downloading Krita, and the problem still persists.
It has to be something wrong with the settings, but I can't for the life of me figure out where the problem is. I've scoured forums, but I can't find anything similar to this. Please help!
I'm running Krita 4.0.1 with Windows 10 if that helps.
[Sorry, I'm new here. If this isn't the right place to post this, then please tell me where I should]

Sounds like somehow your computer is stuck sending ctrl+alt+space+leftmouse button events to Krita, as that icon is the one for discrete zoom, and those are the keys that activate discrete zoom in settings->configure Krita->canvas input settings. Maybe remove the discrete zoom entry there?

Ok...I think I managed to turn off discreet mode and briefly got it to draw something. But the zoom wasn't working at all, so I clicked the zoom tool button. The icon was a normal round magnifying glass. Then it got stuck in regular zoom mode. But then I restarted Krita, and the it was fixed! The only problem now is that zooming is laggy and unresponsive when taking the command from my tablet pen (holding the front button and dragging). It'll do it briefly, then just stop and and start working again and so on (it's perfectly fine when I use my mouse wheel). It's technically workable, but not ideal.