iTunes Backup did i lose my backup? okay so basically I deleted whatsapp and the whatsapp backup available on iCloud but before doing that I backed everything up on my itunes pc 
when i reinstalled whatsapp they said that there was no backup available to restore 
so I connected my iPhone to itunes to restore and it said there wasnt enough space, I started deleting apps and pics while downloading the newest update. 
I thought that during the update it will restore everything automatically but it showed backing up message again and here I freaked out because it will over write my old backup that had the whatsapp messages on it.
Now i tried mulitple times to do a restore and it says that the backup is corrupted! 
Does that mean my whatsapp backup is lost? I tried third party apps for extracation and they didnt work
please help im stuck
If you deleted the WhatsApp backup in iCloud and the backup you had in iTunes is corrupted, then your WhatsApp history is gone.

PS: Unless you have made a Windows backup between the moment you made the last good backup in iTunes and the moment it got corrupted, but based on your description this seems unlikely.