Not really helping your current issue, but something you should definitely read:
3 months worth of work? I'd probably have at least 20 incremental versions backed up in 3 different places by now...
Thank You for a reply. Editing was done inside premiere pro, using hundred of sequences made in after effects. Keyframe animation, characters created in illustrator, animated in after effects and edited in premiere. change illustrator file, and it allready changed in premiere. It was my mistake, not saving a backup version every day. And it was a hard lesson for me. I`ve failed to recover old version of the same file. But before recreating everything from scratch, hope there is a possibility to fix the broken project file.
You seriously need to consider a backup plan for your projects. I cut a feature film a couple of years ago. The project took more than 4 months. We had more than 300 versions of the project saved in 4 locations. We had 4 backups on the network of all the footage. Things go wrong and you MUST plan for that. Save the project with a different name at least every few hours so this will never happen again. Use cloud services like dropbox to store your versioned project files. They don't take up much space.