Disk Capacity 500 gb falls to 250 gb after deleting files [on hold]

I have a 13" MacBook Pro Retina - bought 9 months ago but I guess it's a 2013 model - 500gb hard drive.

As I constantly get "your start up disk is almost full or full", and deleting files all the time, I delved a bit deeper to find doubled up files etc.

I access my iPhoto Library - that was 187 gb. & went into Preview etc., where there were hundreds of files. I removed as many as I could, then removed the remaining folders & files in iPhoto.

When I emptied trash, it said approx. 215,000 files would be deleted. Seemed excessive but I did it anyway.

So, having done that, my Hard Drive capacity is now showing a 250 gb capacity - with only 5.1 gb free. It seems I've lost 250 gb - is there a fix??

Below is the output from diskutil:

Cathryns-MacBook-Pro:~ cathrynggibson$ diskutil list
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *251.0 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            250.1 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *8.0 GB     disk1
   1:                 DOS_FAT_32 NO NAME                 8.0 GB     disk1s1
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *7.9 GB     disk2
   1:                 DOS_FAT_32 CANON_DC                7.9 GB     disk2s1