If you laptop uses an Apple SSD, then your data was securely erased due to how SSDs work. Your personal data has been destroyed.
However, if your laptop uses a spinning hard drive, then your data may still be easily accessible using a data recovery app. Since you did not have Filevault enabled you need to write a single pass of zeroes to the hard drive in order to destroy your personal data. You can also enable Filevault and let the encryption process complete, then perform a clean install once more. Personally I find the latter option easier for most users.
If your laptop has a third party SSD, then I'm not sure if a simple erase is sufficient since TRIM may not be enabled on the SSD (especially in recovery mode). In this case having Filevault fully enabled before performing the clean install is best to be 100% certain the data has been destroyed. I've never tested performing a simple erase on a non-Apple SSD to see if all data is gone like it is with an Apple SSD.
Unfortunately the information in the article @neuroanatomist linked assumes a user is using Filevault or is using an Apple SSD.