Feel bullied by manager, can I get signed off?

basically i was doing overtime and on one of these days i phoned in sick, i was really ill, and i phoned in another day too, he was very rude and said: you better not be phoning in sick. he had the ump when i said i cant come in, he asked for proof that i went to the doctors as if he didnt beleive me... i have done so much overtime for them and everyone else was off over xmas and i was ill and went in, he didnt ask them for proof of anything. i am really fed up and want to get signed off for stess. i am going to write to head offie to complain? my mum phoned because i was upset and he spoke to her like dirt and was so rude. I have really bad OCD and it's making it worse!