It's good to feel a little guilty about not finding the beast but as long as worked hard in your recovery attempt sleep easy. I hit a deer poorly last season and put in a ton of hours over a couple of days and never found him. Sure it's a drag but just do the best you can.
It does sound like if you were finding bubbles than she won't be far so don't give up to quickly and good luck.

The hurt in not finding her also makes for a good hunter.