Relax, even if you haven't backed up your Mac hard drive with Time Machine, there is still a chance to recover files from emptied Trash. You can restore deleted files with iCloud or other cloud storage, and the data recovery software is also an alternative.
Have you uploaded those files to iCloud or other cloud storage services such as One Drive, Dropbox, and Google Drive? If you have, then you can log into your account and download files back to your Mac.
Even if you haven't backed up those files with either Time Machine or any cloud storage, this is not the end. Data recovery software could be the last resort you can apply by yourself to restore those deleted files.
Most importantly, don't continue to write data to the HFS drive once you accidentally emptied the Trash. You'd better not save new files to the drive/volume, edit existing files, etc., given that such operations could overwrite the deleted data, making them unrecoverable.
Then, download and install iBoysoft Data Recovery for Mac to recover files from emptied Trash on Mac. iBoysoft Data Recovery for Mac is professional, risk-free, super reliable, and easy to use. It enables you to freely scan the HFS drive for the deleted files and freely preview the scanned results. Then, you can recover the desired files to a different location. Try it now to recover files ASAP!