Lauren,
I am so, so sorry for your fall and injury. I spent the earlier part of this year in a boot after a similar fall down stairs (I completely missed the first step and fell down about 4 steps). My foot went over on itself so I had what they call a Lis Franc fracture (it involves soft tissue damage and I also had two of the smaller bones broken). It was very painful, so I completely sympathize with you right now.
My only advice is beg for the boot. I was in a hard cast for two weeks and the boot for the rest of the time (I think about 3 1/2 months on that, I had to wear the boot during my rehab also). Promise them you will be a good girl and not take it off and they might let you. The boot is SO much more comfortable and you can adjust the air pressure in it as your swelling goes down, so it fits better and doesn't have the pressure-point problems that the hard casts do. I was not permitted to bear any weight on it, so I was on crutches, but once I could put weight on it the boot was actually not as hard to walk in as you would think, so you might be pleasantly surprised how well you can do in it.
Again, I am so very sorry this happened to you. I feel for you so much right now. I know this is a frustrating blow to your psyche, but I pray that once the early pain has passed that you will heal and feel better soon. It sounds like you have been through enough already!!!!
Lyn