As a server administrator, I frequently run into people who believe that their poor planning is my emergency, and so it's possible I'm somewhat overly sensitive. The use of the word "wrong" might have been a bit strong in this case-- It *is* unfortunate, and I genuinely sympathize with the OP-- and of course, I've never made mistakes (<-- A total lie).
But I still maintain the OP had multiple chances to decide "This isn't going to happen today". Trying to improvise is respectable, but not with chemical processes that require a certain amount of precision and care.
Bottom line, some great pictures were lost. Although, if the OP hasn't tossed the negatives, try to find someone with an Epson scanner-- I realize "over-developed" isn't the same as "over-exposed", but I was able to scan a couple of negatives that were horrifically over-exposed, and still produce a usable image.