You will be penalised. How heavily, we don't know. It depends the level of misconduct adjudged by your assessment officer (which we don't know). Not realising that incorrectly citing, not citing, paraphrasing (which should still be cited anyway) is plagiarism is not a defence: you are a third year, and it behoves you to know what constitutes good academic practice. This sounds harsh but it is nevertheless the position that your institution will likely take.
The death might have some mitigation, but like all mitigation, ought to have been raised at the time and will likely require production of a death cert to be taken seriously. Callous (and none of us really like it), but procedure in the vast majority of institutions.
You are best to cop to it, explain your side with contrition, and hope for the best. The best outcome would be a capped resit, or, a fail: if there is a no detriment policy re COVID, you might be able to disregard a fail. You need to look up the procedures for your institution.