@RecycledElectro ...
I can offer a bit of advice going forward: Always export your course after the semester ends. Then, you can re-import it into a new course or (if your institution is weird and does not let you create new courses) you can create an account on Instructure.com and import it into a new course there.
I *think* you might be referring to the Free For Teacher (FFT) version of Canvas? If so, there are some limitations to be aware of compared to a school that has a paid Canvas environment. One of those limitations is available course file storage in FFT compared to a paid Canvas environment. For example, FFT courses have a limit of 500 MB per course...and this cannot be changed.
Canvas Free for Teacher Account Comparison | Instructure
For example, if you are using a paid Canvas environment and have a course that is 750 MB in file size that you export...that course will not fully upload to the FFT course when you import it there because the *.imscc file is too large. You would first need to trim down the course in the paid environment, export the course again, and then try uploading it to FFT.
I hope this will help to clarify things. Thanks.