Can't mount my WD External Drive

I have an external drive I use to backup my main computer with time machine. I always take it with me to use on my laptop remotely to access files. It was working fine yesterday and now won't mount. The light continues to blink. I see it in the disk utility but when selected there aren't any options available. Says "if you have trouble with selected disk...." as though it's ok. The WD Smartware "CD" icon does mount when it's connected, just not the drive icon.

It was just there yesterday. Tried restarting, re-powering, etc. It's connected via firewire.

Please help! Thanks!