Audio is distorted when I drop it onto the timeline???

I've been editing this one project for a few hours, and when I started, the audio levels were normal and just a few minutes ago, I noticed that when I try to drop an audio clip onto the timeline it's distorted and way too loud unless I adjust the level and bring it down a lot. I switched download link websites and hoped it would make a difference but it didn't at all. Whether I drag it from file explorer to the project bin or when I import it straight into premiere, it doesn't change anything. I'm not sure what to do and my project is due tonight!!! Also, when I try to import a video into Premiere, I get a "file unsupported" red error message, and it only imports the audio.