Somehow my song sped up!

Hi, I am new to Cubase, but haven’t had many issues until just this morning. I finished a song last night, and had everything the way I wanted it. I saved it, closed the program and turned off the computer. I came back in today to listen to it again. I opened up Cubase, then the project file and hit play. I found that the audio had been sped up somehow and is way faster than it should be. The vocals sound very high pitched. It’s almost like the song has somehow been compressed. Any help is appreciated.