Manager threatening to sack me!!!!

I called in sick yesterday to let my manager know that I was not going to be able to come in to work today because I am not feeling well... my manager knows that I am 30 weeks pregnant! She insists that I come in to work because she is finding it hard to find a cover. She said that if I do not come in to work then she will have no option than to dismiss me from work. I'm shocked at how heartless people can be!

-----------

P.s: I have worked with this company for four years and I have called in sick just three times! It is a private company so my manager is basically the owner of the company