Recovery Mode is not available for MacBook Pro I have a MacBook Pro mid 2009 with El Capitan running on it. 

I wanted to enter Recovery Mode and pressed cmd+R until the Apple logo appeared with a progress bar. After about 3 hours waiting the progress bar was complete but nothing happened. I waited another two hours but still nothing changed. 

When booting in normal mode everything is fine and within a minute I can start working. Do you have any advice for me?

The diskutil output as requested by @LexS user87973:

macs-MBP:~ Fab$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *320.1 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            319.2 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
You can have a failing hard disk that shows no errors in Disk Utility. Not all hard disk crashes are due to head landing, they can be electronical components overheat, the electronic components fails gradually slowing down the disk speed to null in a few months. I suggest a disk clone and a swap.