Data recovery is very unlikely if you are using Ubuntu for some time. There are chances that your data is overwritten and hence available to recover in laboratory conditions, but definitely not in the home environment.
Anyway you can try to rebuild partition table to get access to previous partitions. But I assume, that if you didn't backed up your project files, then you didn't have backup of partition table as well. You can try to set up new partition table that is exactly the same as before, but it still don't guarantee any success.
Another option is the help of some data recovery company, but such services are extremely expensive, so if your project is not a life and death matter, I would not recommend it.
Well, to sum up, the best advice:
Make a backup of your important files. Always.