Wow, ur screwed man!
Yes, try "undo" like vance said.
Or download a partition recovery tool. Also try the "fix" option in PM.
If u create a new partition your filetable will be empty, so ur data is lost like wansingct said.
U can create a new partition and use file recovery software afterwards. Maybe it can restore some files but not all of them.
Afterwards I would recommend to format everything to make sure there are no problems in the future.
Maybe PM can undo the merge, though.
I would try to recover the partitions first, backup everything and format everything.