Hypermesis gravadium disorder and work

I’m a teacher in the UK and Ive suffered with really severe hypermesis gravadium since 5 weeks pregnant. I’m now 16.5 weeks and still nearly everyday is a bad day. I can’t keep food or water down, constantly vomiting.. but I’ve still been dragging myself into work. I’m a teacher (Primary) and it’s been really hard going into work and acting the same infront of the kids.. but I worry that if I get signed off work- the boss won’t be happy or understanding.

The past 3 weeks, I have been sent home from work once a week because I’ve been vomiting in class and I’ve been so faint- it’s been impossible to carry on. Today I finally

Decided to be brave enough and call in sick and make myself priority... and the boss was really pissed off with me over the phone and hung up whilst I was explaining my situation on the phone. I feel sooo shit.

The school knows i had difficulties with conceiving and then have suffered with 2 previous miscarriages in the past 9

Months. But I feel so alone right now that I’m going through this and nobody understands. It’s not the typical morning sickness, I can’t just get over it. I wish I could. I’ve lost 4 kg when I’m supposed to be putting on the weight and it’s so emotionally and mentally draining as well that I’m unable to eat or do anything I once used to be able to do.

Anyone have any advice on how I should go on about the situation without losing my job? I hate my job with how the staff have been so mean towards me through my difficulties but I can’t survive financially without it (especially now baby is on the way)