and there is no way for me to do so cuz of the huge amount...!
If you go into Administrative Tools>Computer Management>Disk Management will it show you the two missing partitions? If so they may be salvageable. Your backup options are pretty limited at this point.
You could back up what you can see to an optical drive, or purchase another hard disk to install your OS on and then try recovering the data from there.
NEVER run a backup to a partition on the same drive you are backing up, it's pointless. You see why now. ALWAYS back up to an alternate medium.