I lost 60GB!

hye,this is sashank. I am using dell inspiron 1525 for the past 3 years. Now,there is a problem..I thought it's a problem with my hard disk. problem is

when  I was formating my laptop...

 memory of nearly 60gb was in unallocated space and  it's type is extended memory.

But,when I was trying to allocate that memory as a drive....it's showing an error as...."memory is insufficient (0x8004240f) " .

So, I continued my format...and lost 60 gb now. what to do now?