I Am 21 Years Old I Took A Paracetamol Overdose

I am 21 years old I took a paracetamol overdose on Saturday 20x 500mg paracetamol I was taken in ambulance to hospital but refused treatment went back to hospital yesterday and I didn't receive any treatment. I have been having chest pains since yesterday and it hurts to breathe and I don't feel like I can breathe properly and I keep having stomach pains. What shall I do?