Do i have to do them all in the same week?
Viewing post in It's actually playable now comments
Not at all! It's actually impossible, I think the most you can do in a single week is 3, and some can only be done if you dedicate the whole run to them. The achievement screen should let you keep track of which prophecies you have fulfilled, so you can decide what to focus on in your following runs :)
(You also don't have to do them in order)