How to ask to be put on bed rest?

I know, weird question. But I can't take it anymore. I'm low on iron, and have not been sleeping at all throughout the night due to sciatica nerve pains or lower back pain... or i just can't sleep or even sometimes just because my baby kicks too much lol. The most I've slept in days is maybe.... 6 hours total in a day? Because of this I've been drinking pop or sugary stuff to go throughout my day and its really killing me emotionally and sometimes physically. I've talk to my ob and all she told me was I can quit whenever I want to? I mean. ...I don't want to quit. I still have 2 more months until my due date. Help?