Officegirl, I am shocked by the attitude of your boss given you have had two major personal issues to deal with. The most important thing you must do is focus on your own health and get well; your mum will need your love and support and you need to be able to grieve.
I personally have a tendency to focus on work and its importance, but the reality is that is only a job which is an enabler for the rest of your life; the most important things are your own personal health and happiness and the people you love.
See your doctor asap and get a certificate; you shouldn't have to do this but if your employers are not behaving decently then you must.
Take care of yourself. Will be thinking of you at such a difficult time x