If someone told Meghan Trainor to "break a leg" before her 'Tonight Show' appearance -- she took it way too seriously.
She performed her song, "Me Too" Thursday night and turned to face her band for the BIG finish ... which was great. Not so great her pivot back to the microphone.
And you know what always makes a fall worse -- fighting it. Watch ... you'll cringe and then laugh, which is okay since her camp says she didn't get injured.
That right shoe is so fired.