You opened Google Drive, selected the music file, and then what? I'm still trying to understand the process you went through.
To make sure the issue doesn't happen in the future, I suggest uploading your music directly to your Google Play Music cloud library. To do this, go to Google Drive on your computer and download the music files to the computer. Then go to Google Play Music on your computer browser, click on the hamburger menu at the upper left, and click the Upload Music option. Once the music is uploaded to your Google Play Music cloud library, you will always have access to them through the Play Music app, either via streaming or locally (if you use the Play Music app to download the music track locally).