Trouble opening scores

Hi. I'm fairly new to Musescore, so I don't know if this is something normal but for some reason, I am unable to open my scores. Today, I spent hours working on a piece of music and after I saved it, I tried reentering the document, but it wouldn't let me, sayin that the score is invalid. I honestly have absolutely no idea what could've caused this to happen or what's wrong, and I would really appreciate it if you can help me out. In the case that you'd like to contact me, my email is gabrielpiscopo4@gmail.com. I look forward to hearing from you soon.