I was experiencing some of your symptoms such as the "heavy" feeling, couldn't get out of bed because I know I have to go to my super-stressful job. I was also feeling depressed, angry, irritable, just plain ******-off at anybody who came near me at work.
I took time off and did what I've always wanted to do, travel and relax. I didn't care if I loose my job. I pretty much snapped and told my boss that I need some "medical" time off to get my sanity back. Thanks heavens I didn't get fired. But the thought of going back to work depressed me again as my "medical" leave was coming to an end. So I bought a sports car. I figured, at least I can drive something fun and something I've always wanted to a job that stresses me out.
I also changed my attitude. I figured, the company I work for was there when I got there, and it'll still be there when I leave. If something didn't get done, it's no big deal. To top it off, since I adapted this new attitude, they promoted me! Then I learned to delegate.
But some of your symptoms may be something else. You may want to see your doctor & have a physical.
Good luck and let us know how it goes