How to recover deleted track after saving the project ?

I need your help plz.

I’m using Audacity 2.1.3 , on my operation system is: windows 7 professional, 64-bit

before exporting my audio file, I deleted a track form the project and saved it.
this track contains some of the material, and I must have it back.
what can I do ?

This is my final project @ college, and it due tomorrow !!

Not making backups is like being a flying trapeze artist without a safety net. No problem as long as you don’t fall, but if you fall, it will kill you.
Audacity projects do not save the “Undo” history, so if you delete a track, save the project, then close Audacity, the deleted track is gone.