Sorry to hear you're having trouble with your Discover Weekly playlist updating. No need to worry though, we can definitely help :)
Do you see the playlist updated if you log into a different device? How often have you been streaming in the past week? If you weren't streaming too often, or you were streaming with Private Session, the playlist might not update this week.
You can also try waiting a few hours to see if it's just a bit behind on updating.
I had this problem before, try deleting your cache (do not worry your download will not be affected).
How to clear your cache:
Open Spotify application, tap <<your library>> and then settings, scroll down and you will see clear cache, try tapping this. As I said this will only delete the music that you listen without downloading it.
Please let me know if this will resolve your problem.
Great news, it updated on Tuesday and I didn't get a chance to get back to you. By the way, thanks for the months of faultless service! Best music platform I've been on, if this is the worst hiccup I'll never leave!