Have you stored new file on the same memory card?
The new data will rewrite the original data and wipe it forever.
Therefore, as long as you have not rewritten your wanted files, you do have the chances to recover your data. You could try a free memory card recovery tool that has ever helped many web friends retrieve their precious photos, videos and files, including me. So, you could give it a shot. Note: After the recovery process, you should format this card to make it work again.
You also should learn a lesion to do regular data backups in the future.