Oh boy, 6 months is so young. My DD is 18 months old and still wakes every 1-3 hours to nurse, but because we cosleep, I hardly notice and it feels like I get a full night's sleep.
We didn't start out cosleeping, and while my DD slept through the night in a crib from 2-4 months, she started waking up more at 4 months, and by 6 months, she was waking up within minutes of being laid in her crib. I was, and still am, completely against CIO, so I spent all night nursing and rocking her to sleep, trying to put her in her crib, responding a few minutes later when she woke up. Neither she nor I were getting any sleep. However, the night we started cosleeping, that changed. Yes, the very night. Having a warm body snuggled up to her meant that she slept for several hours, and when she did wake up to nurse, I just latched her on and went back to sleep.
For the sake of your baby's needs, I encourage you to find a way to cosleep. I understand that your room is small, so my recommendation is to take your mattress off its frame, and put the mattress directly on the floor. This makes the mattress seem bigger b/c you can sleep right up to the edge without fear of falling out of bed. If you have the room, I highly recommend putting two mattresses next to each other--even if you have to clear everything else out of the room.
Then, the next step is to babyproof the room--which should be easy since it's so small. Put covers on the outlets, make sure there are no dangerous blind strings, hide all cords. Now, when your baby needs to nap, you can lay on the mattress with the baby, and your toddler can play in a safe room with some quiet toys. Even if you don't nap yourself, you can at least rest quietly while your baby naps. (I use this technique when my DD wakes up too early for my taste.
I close the bedroom doors, drag out her basket of toys, and lay back down on our mattress on the floor while she plays. She will play for a while, crawl to me to nurse for a while, play for a while, and sometimes even come back to bed to sleep more.)