I would try and not be too self-critical; unless you have been given a firm no, then all is not lost.
Regardless of the outcome, you have now been through a recruitment process, and the experience you will have now only puts you in a better position for the next.
As has been touched on within this thread already, opportunities arise, and whilst it may not seem like it now, a positive attitude will always work to your favour.
I attended an interview with Ryanair 2 years ago. I walked out with my head held high; I wasn't cocky, but I also struggled to find fault in what I had done in the sim or interview. I was rejected, and like yourself I started to believe I had lost my only chance; the only thing I had heard for 2 whole years!
Fast forward a year, and I was lucky enough to secure an interview with another UK based airline. Still with low hours in my logbook, I knew how important it was to nail this sim, and I guess I over-thought the entire thing. I walked out and felt completely destroyed; whilst I flew the procedures, nothing felt as 'tight' or as 'accurate' as I had done previous, nor what I knew I was capable of doing. I also felt my sim partner had easily out-performed me, which only made me even more self-critical of my own performance.
I was offered the Job 3 days later.
Being self-critical is part of this game; having a passion for flying, self development and a thirst to learn more will further develop these traits. Most of the guys I see coming out of the sim are the same as me; all quick to self-debrief.
And as with Luke, had I of been offered a role with Ryanair I would likely be posting my ramblings on a whole different thread within this forum. As it stands, I am employed on a decent contract, and most importantly with a company I love working for!
As one door closes, another will open.
I hope you get the news you hope for!