Rob, "crashed" is a word that covers several different types of failure. Not having access to examine your drive, I can only give you several possible situations you may now have, but it is not necessarily the case that your file containing what you call "my tree" cannot be recovered without resorting to very expensive services.
For example - if "crashed" means that you cannot boot your computer, it is possible that the data on your hard drive is completely destroyed, but it is more likely that one or more files needed by your operating system have become corrupted and all or most of your data files are fine. In that case, if you remove the hard drive from the computer and add it as a secondary drive on another computer, when you boot the other computer, you will have access to the data file containing your genealogy data. From there, you can copy it onto a flash drive and your drama will be instantly ended.
Another question is: In what way did your backup drive fail? Were you expecting it to be an exact copy (usually called "mirror") of your original drive but now you find that you cannot boot it … or are the contents of the drive not readable when it is used as a secondary drive in another computer?
Bottom line - all is not necessarily irrevocably lost, but to determine that requires more specific information from you as to the nature of the failure.