I uninstalled my minecraft then reinstalled it and synced my worlds and the world i have been working on has chuncked missing

When i got on minecract today it said to reinstall minecraft if it had accadentally been put on 1.2.14.3. So i did and i synced my world and got them back and the world i most use is destroyed. It has chunks missing from it. Is there any way i can fix this or is it just something i have to deal with? Also my minecraft version is 1.2.13 amd not 1.2.13.54