Sorry to hear about that, that stinks.  The mental aspect seems like the bigger block to your success based on what you're saying.

My two recommendations would be to go see a PGA Professional for a lesson.  That will probably fix the issue quickly.  The other is what my instructor told me:  "Bring the club well inside where you normally would, weight on the front foot, and don't decelerate." 

I hope this helps and good luck!

Been there, done that. Green side bunker play was by far my greatest fear. Now I have none. I took a lesson from a PGA pro but PM's Short Game tips helped a lot.  Basically it is hinge and hold and keep the club head moving except for the up hill plugged lie under a lip. Also check out the Golf Channel's Golf Fix. Lot's of video to help you. The green side bunker basics for me is keeping your weight forward on your lead foot and not shifting the weight during the swing. Open up your sand wedge where you could put a coin on it and it not fall off at address and then regrip your club. Hinge your wrist immediately on the back swing and hit an inch or two behind the ball and let the bounce of the club glide just beneath the ball. You must continue accelerating through the sand. GP used the term like striking a match on greenside bunker play. Another thing to keep in mind when you practice is that 90% of green side bunker play is about 10 yards. Of course there are all kinds of situations of how the ball lies in a bunker but just start with the basic level lie and practice. It took me a year to gain the confidence of having no fear and I still occasionally take more than one swing to get out and sometimes even blade the ball over the green but hey, that's golf.