stcalico is spot-on, if you restrict calories too long your system will adapt and metabolism will slow to match your intake as a form of self-preservation, it can be scary to break that cycle but don't fear it too much, it can be done. I was somewhat the same at one point, had been up to 270ish as a teenager and got down to 192 lbs. in my first year of training, but starved myself for most of a year and was living off of 2000 cal./day while weight training 5x/week and running 6 miles/day at least 3 times weekly. Basically, my body was in complete famine mode, and made the most of what it had but wouldn't lose any fat. If cutting calories were all it took to lose fat, we wouldn't be bombarded with various diet plans, fat loss products, etc., so that's the golden rule to keep in mind in that restricting calories does NOT necessarily produce the results you want.
I found that my best way to lose fat is keep protein high, carbohydrates to a low/moderate level, and to get a fair amount of healthy unsaturated fats daily. This allows me to eat MUCH more food without gaining fat - but, I do have to sacrifice a lot of the convenient things I used to eat that revolved around bread, rice, and pasta, which used to dominate a lot of my meals years ago. Some of us just respond differently to various macronutrient ratios, I cannot lose fat and have a carb-heavy diet (not counting good vegetables, a bit of fruit, and a few whole grain items), but now all my meals are prepared around protein as the base and everything else is planned secondary to it.
Another thing - excessive cardio on top of restricted calories will only hurt your goals further. Ditch the cardio ASAP for now, and consider moving to weight training instead. Cardio does NOT help you build any muscle (which will adjust your body composition, even if you did not lose any bodyfat for a bit but put on lean mass, you'll technically be leaner over time and will have a lower bodyfat percentage), and will starve off hard-built muscle faster than you can imagine, especially with a low-calorie diet. Pain does NOT equal gain for cardio work, sure you may be improving your endurace, but you're also making sure you're not getting any closer to your end goal at the same time. A sound, sensible weight training protocol done for a few months with minimal cardio (perhaps 2-3 days of moderate paced 30 minutes walks, but no more than that) would be a better approach for now to kick-start things a bit in the right direction. More muscle = more calories burned, which will get your metabolism moving in the way you're hoping. After all, if what you were doing was actually going to work, you'd have reached your goal by now, so it's time to abandon ship on your previous approaches and start from a new angle.
So, my recommendation for a potential turnaround on things would be -
1. Increase calories to 2000 per day for now. Make it primarily protein (something like 2 servings of Vega One twice per day would be a good start, that'd get you most of the way there), or, something similar that's protein-dominant and has no crappy empty calorie carbohydrates in it.
2. Start a sensible weight training program that will get you in the gym 3x/week initially. Not "train until you die" with endless sets and reps, rather something that focuses on good compound movements to hit legs, upper and lower back, chest, shoulders and a bit of arm work (don't worry about ab stuff, it's not going to help you lose any midsection fat). 60 minutes max training 3 times per week, maybe alternating upper and lower body workouts, done with free weights and lifts that have proven to be good like squats, deadlifts, benching, rowing, pull-ups (or, pulldown machine) and overhead presses should be the base.
3. Each week for the 6 weeks after starting, increase calories by 100-150 calories/day with good whole foods (you can begin to incorporate more quality carbohydrates at this time and not just protein), maybe a bit of good fats like olive oil or coconut oil, as once you get into the weight training you're going to need more calories for recovery. You want to SLOWLY acclimate your system to getting used to the extra food intake, and unlike with cardio, after weight training your body will actually do something good with the extra calories by helping build more muscle.
You may find in time that with such a system, you'll eventually be eating 3000+ calories per day once your metabolism gets back to where it should be (I eat around 3300-3700 cal./day on my training days, around 3000 on my off days now), so long as the food is what your body is making proper use of and you're responding well, things will work out, but there also needs to be PATIENCE, nothing is going to show amazing results overnight, but after a few months, you're going to see much better results than you are by starving yourself and running your body into the ground with excessive cardio that's only killing valuable muscle mass while keeping your fat levels the same.
There's no perfect way that we just happen to fall into, some of us have years and years of experimenting under out belts and are still figuring things out, myself included. If we could all lose fat doing the same thing, there'd be only one diet and exercise program you'd need, and obviously, that isn't the case. Follow what has been proven to work, avoid the things that are keeping you in a rut, and I'm sure you're going to be closer to your goals in due time!
"A 'hardgainer' is merely someone who hasn't bothered to try enough different training methods to learn what is actually right for their own damned body." - anonymous