Don't get why she's keeping your papers lmao? Apolgoes for the long reply, but the things that have helped/are helping me:
It might be worth picking up a grammar exercise book, or using websites online. Another idea is trying journaling in German - I'm not sure how you'd go about it, but personally I focus on clearly explaining what happened at school, what me and my friends did etc. - It not only helps with vocab (I'd usually have at least one 'paragraph' on a random chosen topic), but also sentence formation, as I practice a specific grammar point with every day (ex. yesterdays was genitive, so I spent half the page talking about other peoples mocks and stuff, and the day before was um...zu clauses, so I felt very sophisticated blabbing on about in order to ... 😂)
In terms of having a set sentence structure, the journaling should be able to help with forming different sentences - you could create yourself little rules for each day, say you have to have a structure which includes a subordinating conjunctive (like weil) on ever other line, and a comparative (like aber) on the remaining ones (if that makes sense lol). - If you timed this, it might get you used to working and creating the language under a time constraint without it being too pressuring (hopefully), which might help with panicking in the actual exam.
Also worth setting aside maybe 5 minutes a day to test yourself on adjective endings and the identification of the cases, I've unfortunately not yet found a way to revise these beyond good old fashioned self-testing (making a grid of the endings and filling it in, then marking) or using online gap fills (which would also test your identification of the tenses), however I can give you some patterns I've noticed within the 'categories' (der/die/das endings, ein/eine/ein endings, no article endings), which are saucepans (as highlighted in bold) of the ein/der systems
(der endings as in the endings of the article itself within the diff cases - I found it relatively easy to remember to a specific rhythm, almost song like, so I'd recommend remembering these with some sort of rhythm)
Once again, sorry for the absolute essay, but i hope it is of help somehow! 😄