We have a full-sized bed for the same reason--little space, less money. WE cosplet with DS! until he was 10 months and rolled out of the bed one night. IT worked out just fine, we cuddled, I nursed, it wasn't a big problem.
Once he was on his own little bed--a single (smaller than twin) futon on the floor, someone usually slept down there with him for at least part of the time. When DS2 arrived, our big guy wanted back in the big bed. We tried it for a while, but no one was sleeping. Eventually DS1 wanted to go back to his "tiny" as we call it, as long as someone came with him. So we play musical beds, and it's okay.
If I had my drutthers, we would have lent our full-sized bed (a beautiful antique my grandmother left me) to someone in the family, forked over the cash for a kig sized bed (with lots of storage space underneath to make up for the dresser we would have to give up) or at the very least a full or queen sized futon directly on the floor (hard to imagine getting on the floor now, at 3 weeks to your due date, I know...). WE'd have been a bit more comfortable for certain. But I would never have given up on co-sleeping for those first several months. There were many benefits--but the greatest on was being able to nurse as needed without climbing all the way out of sleep. Plus there is the yummy factor. Sleeping babes are delicioso....(even if their toes are in your ear)
Congrats on the babe....