I was going to suggest the obvious answer: working - but as your a medicine student, I fear this may not be as good an idea for you as it is for most, due to the (I hear) demanding nature of your course.
My first thing though would be to talk to the university and find somewhere cheaper to live. Based on your maintaince loan, I take it you are not in london?
There is no way you should ever be spending nearly 7 grand a year on accomodation... ask your university to swap you over, or at least put you on a reserve list for cheaper accomodation.. given your money situation I doubt you could even go to ensuite, so try looking for non-ensuite non-catererd halls, if the university has them.
If they cant to do that, and there is no room to budge at all from the university, then you may need to look at living off campus. I can guarantee you will be able to find a room in your city (as long as its not London) for a lot less then 7 grand for the whole year. I mean I used to rent a 2 bed flat with a garden for £6500 in comutable distance from liverpool, let alone just 1 shared room in a large house. My sister down in bristol rents a room in a lovely house for around £325 a month, which even including bills is around half of what your paying already.
----
Once you have cut your accomodation bills down, then you can start to look at part time work / other sources of income to top up your money, and it will be much more feasable for a medical student, as you will likely only need to work 1 day a week, rather then the 2/3/4 you may need to work with your current accomodation bill.