Your university will be working through its processes, the first of which is to offer you a standard resit package for the summer. What happens next, if you don't complete them, will depend on the specific academic regs at your uni, so the first thing you need to do is check them out or speak to someone who knows them inside out.
I'm actually quite shocked that you were able to get through the whole year without doing any assessments. Did the uni not attempt any interventions via student support, your personal tutor, etc?
As you acknowledge yourself, completing 13 assessments in the next two weeks is not a realistic proposition. However, it might be possible to submit some, though you would have to be quite strategic.
You really need to engage with your personal tutor, programme leader and any support staff within the uni for proper advice.