Sick leave

Hi, I need some advice.i am single parent of 2 children. My older is 18 still at school and suffers with multiple mental conditions. My younger is on safeguarding due my older mental problems. Recently I am unable to work. Due to stress and lack of help I am constantly on emergency room due to high blood pressure. We unable to sleep as my older screams; I am feeling and looking like 20 years older than I’m. Recently ambulance crew told me I should speak with go and ask for long sick leave due to stress as it affect my health. Can I really do it? Won’t I get fired?