I hope your Sunday has been good so far! I woke up and had breakfast and then I visited a German Lutheran church (interesting experience for those who like history and theology!) Now I am just chilling at home thinking of how to spend the rest of my Sunday....
A big struggle for me in the beginning and I believe for many that come to Germany, is the fact that absolutely everything except for some restaurants is closed in Germany on Sundays! So basically you have to plan ahead for your food shopping and if you get sick, otherwise you'll end up buying overpriced milk at a gas station...
If you have an emergency and desperately need medication, there will be ONE drugstore with an emergency staff there. The drugstores take turns every Sunday so you have to first find out which one is "open" and then you need to call them or ring the bell there because the doors are closed, and they are only there for emergencies (so unless you really need it don't bother them!). Otherwise, you'll need to go to a hospital.
The shops are ALL closed and there is no way to buy anything not even food in the supermarket! The reason for that is that Sunday is a holy day and people are supposed to relax and enjoy the quietness. Many apartments have rules such as "not washing clothes on Sunday" because it would be loud and bother the neighbors. You can also get a fine from the police for being loud on Sundays and it can be as high as 2,000 euros!
So some ways to enjoy your Sunday here are really relaxing and doing nothing, going for a nice walk, eating out and of course there's always the movie theater!
I hope you have a wonderful Sunday in or oustide of Germany!