If you feel the final grade does not accurately reflect the conditions in which you achieved it, then your best bet is to appeal. I don't think anyone is going to be able to say whether it'll succeed or not, though - it really all depends, firstly, on how much evidence you have of your extenuating circumstances, and secondly, on how aware the university were throughout your degree that you were experiencing all of that.
Investigate and follow the university's appeals process, provide all the documents and evidence they ask for etc. Make sure you're familiar with exactly how the process will work.