Where's my Camera Roll?

I was deleting a lot of photos from my camera roll, and gained a huge amount of spaces. But then I don't know what happened an iCloud message(?) popped out which I accidentally clicked allowed, and later found out that it takes 2GB of spaces for my photos. Also my Camera Roll suddenly changed its name to 'All Photos'. I don't know what happened? What is taking up the space in photos suddenly? And where is my Camera Roll?