Lost all mine, thousands of bookmarks, finally found workable solution on a google forum, here it is, kudos to Leo, all other solutions failed:
In win7 your bookmarks are stored in C:\Users\YOUR USER NAME\AppData\Local\Google\Chrome\User Data\Default
There are two files here:
Bookmarks and Bookmarks.bak
Right click on one of them and click "restore previous versions". It will look for other versions for a while and give you 3 previous versions to choose from. Choose the latest one. Do the same thing for the other file. Now turn on Chrome and your bookmarks are back. If they are not back, try restoring and older version of those files.
I would advise saving a copy of both files to a separate folder(a thumb drive too) every few months.