From the research I’ve done it is possible to turn sexual energy into something more positive through sublimation. I am in an environment where my sex drive is high but I don’t want to use it. 

I love to write stories, draw, read, and do yoga.  Yoga is one of the few things that helps me relax and even feel oxytocin besides masturbation. 

The problem is that even when I keep myself busy during the day, going to sleep is difficult. I cannot hide my phone as I am living in the dorms. And even without porn I’m very capable of masterbating. My Roomate is not always at the dorm and so I have many days by myself. I try not to spend very much time in my room but it’s always the nighttime that gets Whenever I try to sleep I get hard, or whenever I’m on my bed I get hard. Maybe it is part of my history of masturbating before I go to sleep as a kid. And so even when I have another person in the room, it’s very difficult to resist.

Even if I try to read in bed, I get hard, and usually it’s very  long books about history not erotica. 

how can I de-sexualize my room? And how can I transfer that sexual energy into something useful?

So your room isn't inherently sexual much more likely it's that pavlovian response to getting into bed... which will take time to go away.
on top of that halachily you are supposed to sleep on your left side. Sleeping on your stomach can cause you to spill seed I forgot the reason for why not to sleep on your back and then your left side is better then your right side for digestions so if you haven't done so try that.
Now aside from all that reorginizing your room and getting rid of junk you don't need can help with making a transition so a little bit of fengshui and decluttering can help an organized room is an orginized mind... 

I can't see the full layout of the room but I would switch the places of the dresser and the desk and get rid of all the clutter from the tops of both and maybe rearrange the posters somewhere else split them into groups the comics stuff by itself and the geographic stuff with the Albert Einstein quote and whatever it is in-between them...  that last suggestion is bit neurotic of me lol.

I generally clean my room on Fridays. But it’s not usually like this. It is probably a Pavlovian response.

Speaking of dogs, though I was able to meditate and remove my urges. I grew up with dogs, and so I’m very good at understanding their psychology. And so I imagined my urges/penis, being a dog begging for food. When they beg for food, they whine and complain, and they look very cute and you want to give it to them but you should not. So then you put them in the crate and they’ll still complain but once you ignore them, they’ll eventually figure out that they should stop complaining. Eventually, let them out and they behave well. 

Dogs are also not sexual in the slightest way and still thinking about dogs can remove those thoughts but also make me think of something positive.