Okay, will talk to my bank, sadly not BAföG-eligible anymore because a switched my topic too late. Thanks for the advise.

Yes i thought about the option to take a loan if something happens, but in my situation i need every cent to get by, I wont have anything left over when the month ends. Paying back a loan seems impossible without working more, but then again I want to have as much time to study as possible. Would it make sense to go for a "Studienkredit" where I get every month 200-300 extra to build up something on the side. The loan would run for 3-4 years with 3.6 ppa. After finishing university i could sell the apartment and pay back the whole thing at once.

One period would be manageable, but any more than that would be hard to compensate

I'm in Germany, buying a new property is not an option for me, as I want to live in a shared apartment with people from my university.