please help!!!!

I am 13 weeks 4 days and have had the worst head pain I have ever felt I could actually kill myself at the worst of it. I am in hospital on Iv pain killers and fluids and it eases the pain without it I can't move my head or walk or anything.... 
They want to do an MRI to check for a blood clot on the brain. 
Has anyone had this before in their pregnancy???