Some workplaces really are horrid. Sorry you are going through this. You really can't go back to work, it's not safe for the other staff. Its a reportable disease, one that the federal govt considers serious enough that they track all incidences of it. Your boss may be at risk of legal action by other staff if he forced you back to work.

I know how hard it is though - my family are 3000km away so we have no support at all here. Illness is definitely the time when it strikes me how hard it is. Good luck