Since you are hypothyroid, it's possible that your hypothyroidism has not been addressed properly and your adrenals are being stressed. Low cortisol causes anxiety. A good site to go to in order to get the proper labs run is http://www.stopthethyroidmadness.com.
There is a section on recommended lab work. (http://www.stopthethyroidmadness.com/recommended-labwork/) Often, doctors do not run the right tests. To confirm adrenal fatigue, a 24hr saliva cortisol test should be run. A couple of test to do at home to determine if you might have adrenal fatigue is on the above website too under the link: THOSE DURN ADRENALS.
* Take your temp, 3 hrs after rising and every three hours after that for total of three times. After the last reading is taken, average the day's temp. Do this for at least 5 days. If your temps vary by more than .3 of a degree, suspect adrenal fatigue.
* Go in a completely dark room or closet, with a flashlight and mirror. Shine the light at your eye from the side of your face and look at your pupil. If it doesn't stay constricted or flutters, suspect adrenal fatigue.