Interesting flush Ain! The rice-shaped small things you got out almost sound parasite egg-ish..only they were really dark, so I just don't know! As we say here: better out than in!
I gave them a very close look and they were not eggs. They were of the same stuff as the stones I passed two weeks ago. They seemed to be made of grease. My guess is that it was cholesterol. They mushed between my fingers like warm butter or fat.