I had my biggest downswing late last month. What helped me was to stop playing for a few days and just clear my mind. Went to the gym, went out with friends and then came back and reviewed some of my losing sessions.

 The biggest thing that I noticed , among many small mistakes, was that I was playing scared. Meaning that I wasn't making thin value bets, because I had been so conditioned that every time a scare card came my opponent hit it or every time I would value bet an over pair I would get shoved on the river, etc. 

Not saying this is happening to you, but there is no doubt your game is being affected by this down swing, I suggest taking  time off and then look what small mistakes you were making that also contributed to it. And keeping in mind that as long as you keep making +EV decisions everything should balance out in the end. And gl...because I know how shitty it feels to be in that spot. 

Ive a one like that a while ago, i was playing decent maybe not supper sollid, but def not tilting etc, just losing all the flips and coolers and bam down 30bi (ev was breakeven).

I think you can do a couple of things, move down, play less tables and try to play your A game more ofthen, that way you edge will be the biggest it can possibly be and thus reducing the variance.
And ye def try to stay cool mentally and dont tilt, its ok to lose because of coolers, setups or mistakes even, just a much bigger problem if its cause of tilt.

Work harder off the tables. Review your hands with someone and grind out the "boring" stuff like figuring out your ranges in different spots, knowing what a 4 betting range of 3.7% means, study the guys who crush etc.

Take a couple of days off playing, a week if you need it.  In 6 months time you'll thank yourself.  Go to the gym, hang out with friends, just take some time away from poker.

Use that time to do some theory work as JH said.  But take at least a day or two off completely and try and turn your mind to something else completely for a while.

Get drunk , chase girls, don't think about poker. Then review hands, get hungry to grind again.  If you don't get hungry to grind again, wait until you do

Tried everything, but it hasn't worked.
Today will be my first even day in two weeks, and again I ran 2k below EV.
Spent 7 months studying and I'm not going to fuck it up again, but when I run this badly, I really don't know what to do.

I'm currently on a 40K downswing myself. It doesn't affect me mentally so much because I'm not making mistakes over and over again - just getting unlucky and that's okay. Just keep your cool, take a break and follow good BRM. I know the feeling you get when you can't win a single pot, or keep losing flips after flips but that's just the nature of the game. It's cruel and you just have to endure until things go your way.

Just recently I experienced a prolonged downswing myself (+100 buy-ins as well), so I know what I´m talking about and I know how difficult it is to a) give good advice from "outside" and b) get advice that is really helpful to oneself w/o the risk of getting offended.

Still, what really bothers me is the speed you´re showing up with. 55 buy-ins in 5 days? That does not sound good ... how many hands / tables did you play?