My paranoid self won't allow me to buy any furniture unless I've made sure that it'll fit the space. It's okay OP, lesson learned. You'll know what to do next time.

thats. why you dont throw out old things until you get a replacement. unless the first one is really really bad, at least you have a backup

Just camp out in the living room for the time you're waiting.

This story is equivalent to saying you quit your job before you found another job and now you're jobless searching for work. You kind of set yourself up for this failure.

I used to work at IKEA, and the mattress and frames are definitely standard US sizes. You might have grabbed the right mattress in the wrong size or something, but all the bedding IS standard sized. They just don't have California King or anything special like that.

Their sizes are definitely standard..

Just put the new mattress on the floor until the right size arrives and sleep on it, then switch them out.