HELP- My contact list is usless now.

So my contacts list got really messed up when i imported a .csv file to it that a website said would add alll my facebook contact information to my address book. I was under the impression that it would simply either a - create duplicate contacts- or b- add the info along side the already existing info. Well, to my unfortunate suprise - i found out that it erased all my contact information i had in my gmail and I am so frustrated with this because i had a lot of important notes and actual infomation in my contacts list that i wanted to keep in there that were not in the .csv file that i uploaded. I am wondering if there is a way to revert my contacs list back to the way it was prior to importing this .csv file, wheather its on the google end or my end. any help would be GREATLY appreciated.

i hope to hear from you and hope you can help me and save me a bunch of frustration in the future by helping me.