Keep your chin up! Last season I had a 6 egg clutch (pastel x lesser) and I lost 4 of them. All four died around day 30 in incubation. I cut open the babies and they too were kinked up and looking rather deformed. There were no temp fluctuations and the clutch that hatched just 10 days prior to this one had 10 healthy babies. On day 56, a pastel and a pastel lesser female pipped.
It could be that you just had bad luck with that egg. Things happen. At least you have a good sized clutch to have faith in!