Firefox has seemed quite glitchy to me lately. Not just here but other places as well. Although I'm not normally a fan of doing so, have you updated to a recent version lately? I inadvertently did that on the desktop computer a couple of months ago and it's been problematic. If so, also don't forget to update your ad blocker.
My motto - if it ain't broke - don't fix it! I did here also that Firefox had a MAJOR crash a few months ago. That also might be part of the problem.