After a failed bootcamp attempt, my 2 TB Fusion drive capacity is sliced in half.

So last night I left my hard drive partitioning away with Boot Camp assistant. When I check, I saw no new hard drive symbol on the desktop, so I assumed it failed somehow, and started the assistant new. However, when I was choosing space for the new partition, I realized something was wrong with the hard drive. I ran diagnostics, but the hard drive checked out somehow. I need help, and fast!