Yes, those were gallstones! Since this was your first flush, it is great you passed the darker stones. I didn't pass these stones until the 3-4 flushes. I never passed a red one, but I read on this forum yesterday that they are the most toxic.
Yes, you have shocked your gallbladder, so it will be a day or two before it recuperates. But, more stones are now moving forward ready to come out in 2-3 weeks. So, keep flushing until you are stone free.
Whatever type olive oil works for you, I say go for it!
Now, it is your job to "spread the word" to your friends about this wonderful, life-saving flush.
Good luck and good health!