Recorded audio is one semitone lower than yesterday [SOLVED]

So yesterday i decided to record some simple guitar riffs, and i use audacity to quickly record ideas on the spot, since its just opening the program and pressing record.

Today i wanted to record a little solo piece over it, but it seems that when i record the solo, and play it back, its suddenly one semitone lower than what i actually played, and of course it sounds HORRIBLE over the track i recorded yesterday.

What happened? Why did it suddenly change?

I tried to fix it with pitch shifting (it even registered the first note as an F even though i played an E, wtf?) but it completely messes it all up…

I can upload the tracks on youtube if you would like a look.

You probably have a mismatch of sample rates somewhere.

The default sample rate for Audacity is 44100 Hz (the same as an audio CD). Look at the “Project Rate” (lower left corner of the main Audacity window) and it should say “44100”.
Then look in the “Recording” and “Playback” tabs of the Windows Sound Control Panel and check that both the recording device that you are using, and the playback device are also set to 44100.

(if they are not set to 44100, make a note of what they are set to before you change them.)
Ideally they should all be set to 44100 (if possible).

That fixed it! The playback device was at 48000 hz. Thank you!