I am curious as to just what your disability is. Are you in a wheelchair, or have some other condition that qualifies as a disability?
There are several things you could do to be able to sleep in your own room instead of on the couch. Your mother offered to buy you a new mattress, take her up on it. If it is too hot, get a small window air conditioner for your room. Buy an ionic air cleaner to keep the room fresh. If the lights in your room are too bright, put in lower wattage bulbs.
Get off that couch and exercise. Stretch, ride a bike, take a walk, do yoga, pilates, swimming, anything to keep you moving. If you can't find a paying job at the moment, donate some time, maybe a few hrs. a week at the local hospital. You'd be surprised at how much better you will feel helping someelse and getting your mind off your own pain and troubles.
Pain can't be treated effectively with an on again, off again basis. It must be treated on a regular basis with consistency. Some Rx's do have the effect of making you drowsy, but quite often this goes away after your body adjusts to the new med. Sometimes you just have to keep trying different meds to see which ones or which combination works best for you. Not all meds work the same for everyone. If your doc wants you to try something, ask him or her for samples, doctors always have lots of samples.
I'm sorry if it sounds as if I am being harsh and not understanding what you are going through. I really do understand, I have lived with fibro for almost 55 yrs. now. If I spent most of my time lying around or sleeping, my life would have been a misery. Sometimes you just have to pull yourself up by your own bootstraps and say: "This is not going to dominate my life and dictate what I can or can't do". The right attitude can do wonders for your outlook and your stress. Remeber, if you reduce the stress, you will reduce your pain.