Intern at a small company, I completely ruined their git branches.

I'm panicing a bit. My boss asked me commit the changes i made to the master branch on bitbucket. Problem was, the code was copied to my machine originally by downloading the files from our bitbucket and unzipping it into a folder onto my machine.

After some googling I tried many things, eventually my changes ended up committing, but I managed to remove all of the old commits. After some more googling i managed to get all of the old commits on one branch and my new code on the master branch, not attached to any other commits.

Is there a way I take all the old commits and put them back on the master branch? Thank you.