I am sorry to hear that you are struggling with your assignments, and I would echo the advice above.
For my University, we are able to ask for a few day extensions (around a week more time). If there is something similar at your University, I would recommend getting an extension. (However, there may be a certain number of times you can apply for extensions. It would again depend on your University).
I think the best way to know is to contact your divisional team for support, they will be in the best position to provide you with support, and let you know the impacts of getting an extension.
I hope this helps. Good luck.
University of Kent Student Rep