Drush stopped working, command not found

This is really weird, I had Drush installed and working perfectly last Friday. I come in to work today restarted the computer and tried to execute a drush command and I get a command not found error.

I thought maybe something happened to the alias, but the alias path is still correct. I went into the drush directory even, and I get the same error. I can see the drush file in the directory. I then thought it was a permissions issue. I set the chmod u+x drush and still get command not found. Then I just chmod drush to 777 and still get the same.

my alias inside the .bash_aliases file ... alias drush='~/Sites/drush/drush'

below is a ls -al of the drush directory, and like I mentioned I can't even get the command to work in this directory.

drwxr-xr-x@ 17 dan  staff    578 Nov  1 16:41 .
drwxr-xr-x+  7 dan  staff    238 Nov  1 16:23 ..
-rw-r--r--@  1 dan  staff     22 Oct 31 12:55 .gitignore
-rw-rw-r--@  1 dan  staff  18092 Sep 17 21:50 LICENSE.txt
-rw-r--r--@  1 dan  staff  11484 Oct 31 12:55 README.txt
drwxr-xr-x@  7 dan  staff    238 Oct 31 12:55 commands
drwxr-xr-x@ 10 dan  staff    340 Oct 31 12:55 docs
-rwxrwxrwx@  1 dan  staff   3285 Oct 31 12:55 drush
-rw-r--r--@  1 dan  staff    743 Oct 31 12:55 drush.bat
-rw-r--r--@  1 dan  staff   1142 Oct 31 12:55 drush.complete.sh
-rw-r--r--@  1 dan  staff    165 Nov  1 00:09 drush.info
-rwxr-xr-x@  1 dan  staff   5550 Oct 31 12:55 drush.php
-rw-r--r--@  1 dan  staff  23280 Oct 31 12:55 drush_logo-black.png
drwxr-xr-x@ 13 dan  staff    442 Oct 31 12:55 examples
drwxr-xr-x@ 18 dan  staff    612 Oct 31 12:55 includes
drwxr-xr-x   3 dan  staff    102 Nov  1 16:41 lib
drwxr-xr-x@ 31 dan  staff   1054 Oct 31 12:55 tests
Dans-iMac:drush dan$ drush
-bash: drush: command not found
Dans-iMac:drush dan$

Anyone know why it would be working one day and now it's not.

I'm using a DAMP install on my Mac running OS 10.7.2
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