Hi,
I totally feel for you, as I was in a similar situation a year ago. I used to cry on my way to work - and in the toilets at work.
Please don't feel as though you are trapped. You need to make an appointment with your GP(hopefully he/she is understanding).
If you are worried about getting your point across, make a list of all the things you want to say and show it to your GP.
I was signed off with stress and depression, initially for 2 weeks. When I went back to see my GP at the end of 2 weeks, he signed me off for a month. Personally, the more time I spent away from work,the more I knew I couldn't face going back.
In the end, I got signed off for 2 months at a time and after 10 months I resigned. I didn't have to work any notice or anything.
If your job makes you ill and has a negative impact on your life, it is time to look at other options.
I couldn't afford to give up work at first, so I stuck at my job for 4 miserable years.
We have a lot less money now, but I don't wake up feeling sick any more.
Good luck - keep me posted. {hugs}