Opened an example project in unity with my existing project open, can't go back?

Hi I'm super new to Unity and I'm doing a project for school that is a simple sidescroller, I recently imported SimpleHealth Bar free and made sure to save before doing so. I was following the tutorial after import and clicked on the example_asteroids as instructed. I realize it could have been a bad idea to do while working on my project however I took steps to prevent this overwriting anything by saving preemptively before I imported the file. I figured it wouldn't be a big deal to try and test it out since I now had my game backed up to the most updated state. I obviously miscalculated and couldn't close it so I exited unity and reloaded my (should be normal) project... I opened it and it's still on the scene... So an hour later and here I am posting begging for help because I'm either to stupid to figure out how to exit the scene or I'm even stupider than that and deleted all of my work. Any help whatsoever is greatly appreciated.