I've managed to recover wrecked saves before, but it's been a few years since I have done it and can't remember all the steps I took. Do you use Save Cleaner? I would run that every so often to clear up the bloat in the files. When all else failed, I would use Nraas Porter and pack everything up into a new save. I also got into the habit of making backups regularly because losing a bit of gameplay is a much better alternative than losing it all.
It might be worth a try to see if you can salvage your save first before restarting or re-doing it.