and you sound a lot like me in the I exercise a lot and can't seem to lose weight category. In my case I suspect that I have a thyroid problem, but I won't know for sure until I can get tested-- no insurance. I had the standard test a handful of years ago which only tests for T3 I believe. That was normal. But I've read that you can have problems if either T4 or TSH are low as well or are at the low end of the acceptable range. So you need a full profile.
Back to you. Do you drink a lot of caffeine? especially coffee? Coffee makes you secrete cortisol. It's the fight or flight hormone, but also a "store my fat" hormone! Try omitting coffee if you drink it, and stick to things like green or white tea.
Insulin resistance (aka metabolic syndrome) is tricky, you have to be careful about what carbs you are eating, at least initially. Are you sticking to veggies and some fruits (mostly berries and melons) that are low on the glycemic index? These are foods that are processed more slowly and don't give a quick energy boost followed by an equally quick "crash" into fatigue, even sleepiness. Low GI foods release their energy more slowly and at a more stable rate than other foods. Anything made from flour is out or most grains really, and fruits and veggies with a high sugar content. (If you omit them and start losing weight, then you know these foods were a problem. You can slowly reincorporate them as you reach your goal weight, and probably not eating them as often as you did before.
That's food.
For exercise, have you been doing the same things for a while? If you have, you might consider switching to intervals training for cardio. Do you do any strength training with weights at all? Putting on muscle will help burn calories faster. Fat doesn't use as many calories as muscle does.
Glycemic Index:
http://www.glycemicindex.com/ Interval training:
http://www.intervaltraining.net/ Welcome to the exercise group!