Workplace bullying during pregnancy

Apologies for the long post...

I'm 21 weeks pregnant with twins and have been working at the same company for the last 4 years. When I told my boss I was pregnant I expected some support, especially as Family is considered the most important value of the brand. Instead, he'd tell me that other VPs had commented that I was being lazy and even though he felt it was wrong he didn't know what to do.

Once I told the HR department they recommended that I take Sick Leave immediately. My doctor refused to sign me off as i am pregnant and not sick, and they made it clear they were unhappy about this. Since then I've had my pay cut and received my first ever warning with a threat if dismissal. If I ask for help I'm told, that's your job if you can't do it, you need to leave. I'm not allowed any more sick days and I can't work from home. It's getting me down now and I'm not sleeping, all I think about is work. I want to focus on my babies but all I feel is stress.

I don't know what to do. Thanks in advance for any advice ladies.