No offense or anything but you don't sound mature enough for University yet. A lot of people aren't and it's perfectly okay.
Perhaps dropping out and going next year, or the year after (whenever you are ready) would be better for you emotionally and mentally. I would hold out for a month or so though because it can take people awhile to really get comfortable with the general University lifestyle. It's a shame because Loughborough is obviously a very good University, especially for Sports Science but its not the end of the world.
My advice would be to stop focusing on trivial things like missing your room. If you need to go out and get some things that will make your room more homely. I did and it worked out great, so much so I don't even like sleeping in my own room at home now. It could be posters, rugs, cushions, even the type of duvet cover you use. And like A levels, just get on with the work. Push yourself into doing it whether you're motivated or not. Get up, go to the library, and stay there until a sufficient amount is done. Secondly invest in some earplugs or something. If you really can't sleep well because of the noise (and the noise isn't excessive) then you'll have to suck it up and deal with it. If it IS excessive call security. Lastly keep yourself busy. You said you don't like going to the gym...for whatever reason, so join some societies, run on your own or with a group, listen to music, go out for dinner. Keep yourself occupied an happy. After awhile you can truly decide what is best for you.