Buzzing sound and voice sounds like a robot, help?

I just got my scarlett focusrite 2i2 and blue yeti pro mic a few days ago and it’s been sounding great… But today when I got on Audacity, the recordings were terrible and sounded robotic and had lots of static. The first thing I did today was try to plug in my acoustic guitar to the interface but it had that buzzing noise and I couldn’t even hear myself play.
What happened?

Which Audacity, all three numbers. Which computer, in detail. Did it start doing that when you plugged the guitar in? Or your microphone started doing that and the guitar kept doing it?