Did you explicitly tell the installer to use your /home partition as
/home? If not, then it won't be listed in your /etc/fstab file and so
won't be mounted on boot. Instead, your new install will have created
its own /home directory within its own partition.

The relevant entry in my fstab looks like

# /home was on /dev/sda6 during installation

UUID=96039346-f682-4090-8389-03e0fa01859b /home ext4
defaults 0 2

Why the installer insists on using UUIDs to ID the drive, I don't know.
You can simply substitute the appropriate /dev/sdxx entry for your /home
partition and it should work. fstab must be edited as root (sudo gedit
/etc/fstab).