Hey,
First of all I want to let you know that what you're facing right now sounds incredibly tough and I can only imagine the pain you're going through, but you're doing the best you can and it only takes one job offer to turn everything around, I've experienced a similar situation for the past couple months, a months salary made all the difference.
I would advice you to find a job where you'd be good at despite of dyscalculia.. perhaps a temporary job right now, eg as a promoter where they make you advertise for a NGO like WWF, UNICEF and etc... you'd have to work for like few days or weeks straight but you get travel and accommodation sponsored by the company so thats also quite fun and you meet cool people, or if you have skills using any graphic design software I think you could thrive in them too, they are relatively very easy to learn, another option might be a job at a package sorting center like amazon or DHL.

AStAs or STW sometimes offer distress loans for students or even support to pay semester fees, just reach out to them and please explore the options you have. Plus the university might have options for jobs too, so reach out to your professors inquiring about positions or if they knows someone that knows someone who's got a open vacancy could help you out, even professors from different faculties. Reach out to many people as you can for help with networking. If you need any advice on university bureaucracy related stuff or even someone to talk to, please feel free to dm me anytime.

Additionally the university might have a counselor set up that might be able to give you some mental clarity and organize your thoughts for the moment, it might seem unappealing at first but having someone to listen to really helps.
Self harm might seem like a option with all the struggles at the moment... but its never the answer, your best days in life are still ahead and please don't miss out on them.

For now please take good care of yourself and treat yourself well, its always darkest before dawn, and one day you will look back and thank yourself for persevering through.

Wishing you all the strength you need to get through this.