To the original poster, sorry to hear about your experience. I busted part of my checkride at my first 121 gig straight out of CFIing and can somewhat sympathize with what you're feeling. The good news is that it's not the end of the world! If nothing else, remember this, attitude is everything. You seem to have a good one. That is priceless going forward.
Like others have mentioned, 135 might be a good route for you to sharpen your skills. Especially your instrument skills from what I hear. This will be very helpful for your next try. I think that one of the keys to flying a sim is to not have any questions when it comes to instruments. The only task you want to have is that of flying the box. Your mind should only be concerned with Flows, Profiles and Callouts.
That being said, I'm confident that if you got hired by another regional today, you'd have no problem passing the course. You actually learned alot more than you think from that experience. Give it a shot you got nothing to loose by trying. When you do get an opportunity, invest in some sim time somewhere. It'll better prepare you and will do wonders for your confidence. Very best of luck to you. It's not the end of the world.