The day Lizzie and I would like to forget.....Her first trial

So Liz had her first trial entry. Lets say she will NOT be entering any trials soon and as SOON as her "run" was done I found the trial secretary and asked how to pull Liz from the rest of the trial. The really unfortunate thing is that whole incident unfortunately I think points to a really bad judgement on my part to enter her in the first place. The sad thing is that Liz was making sure HUGE progress, and is a different dog from this summer when we couldnt get her to stay with me and work during a private session and she has come to the point that she can do a long stay with a group of dogs sitting right next to her when I am 30 feet away and jumping and clapping. How great is that and how wonderful the progress. Liz is able to do agility in front of familiar dogs on familiar territory, or I think at a place that I can work for a little bit to get her attention first and let her settle in. To enter a trial Liz will have to be able to walk into an area "cold", turn and give me her attention. We are definately not there. Poor Liz. So the plan was to take her into the ring and set her in front of a few obstacles, let her perform them, get her and run out of the ring. Well, Liz just went way over threshold and when placed in front of a tunnel just took off in a major zoomie around the field. She was so over the top she couldnt even do the one tunnel. I will say when she does that I do not think she is hearing things, she is not thinking she is just feeding off the movement. So thank heavens we were at a yard that had actual gates and was fully fenced, everyone spun into action and slammed the gates closed. Liz did come to me and looked relieved when I got her, and I know dogs dont think this way, but I felt like she was just as upset over what happened, and I felt like she was telling me that she just couldnt help it. I felt so horrible for my little girl. It was all my fault for putting her in a situation that in hindsight I should have known she was just not ready for. It was not my most proud moment as her trainer. The really bad thing about the situation is the whole thing has just made me feel hopeless about her prospects and while we were riding on a high and I was starting to feel like she was going to be able to do anything....now I am just having trouble thinking about even continueing her training. It would just be so much easier at this point to get a nice, easy, fun puppy-although I know there are no guarantees on that, but... I just want an easy, fun dog that I can just have fun with and that everything isnt such a challenge. Can you tell it is a bad morning for Liz and I. I just feel so inept because I just do not know that what I am doing in training is what Liz needs, I do not know anyone who has trained through these things, and so everything is just what makes sense to my pea brain or what feels right and so far it seems to be working but we just get to this point and then we have not gone beyone that, so I really worry that I am missing some little thing that I should be doing. I just wish I knew so much more. To make things worse....I am not sure how obedience class will go tonight. Last week Liz was jumped by a cattle dog WHILE she was doing a recall to me, right as she got to me and her toy. The rest of the class she wouldnt let any dogs near her, she would cross to put me between her and the dog, and she wouldnt look at her toy. Liz and I are hitting a little low right now, hopefully it will pick up again soon.