Don't panic. I know very well your feelings, really! My income depends on my game development, and I've lost like half a year of progress before (though due to Unity, not due to playmaker).
Alex will help you recover. I don't doubt that. Aside from his assistance, there is one piece of advice I can give you that will help you and solve all problems like this in the future (no, really).
First: Always assume there are NO guarantees for anything or anyone else who touches your project.
Second: "Export Project". Do it every day. If you don't have enough space on your HDD, then overwrite your oldest ones after a while. Daily backups. It's a pain in the fucking ass, but the effort is marginal when you suffer a loss like this.
This is not your fault, BUT, if you follow the above suggestions 1) assume nothing is guaranteed, and 2) backup every day, you will never have such an issue again -or- if you do, it will be because you didn't follow the above two steps.
I really sympathize with you, but you have to figure that we developers have no such thing as "insurance", so we have to create our own to make certain our livelihood is always safe. Alex is a good help, so trust him. I wish you the best otherwise!