I did the same thing in my first apartment, which I shared with two friends from college. My room was too small for anything but a bed and one wall was 9 feet,

I did the same thing in my first apartment, which I shared with two friends from college. My room was too small for anything but a bed and one wall was 9 feet, so I built a high platform for the bed with a lower 3' platform as a landing, and a set of stairs leading up to the landing. Underneath the landing I had a closet, and under the bed I had room for a small home office.