The best answer coming from a guy with a biology background is that the medication u r on does simply make you have hot and not so hot flashes, but direct exposure to the sun can cause a higer temp and therefor a hotflash like feeling, stay out of the sun for long periods and once your body excepts the new meds all will come down to a normal avergae daily temp, i know this for sure. good luck
I see you are on a thyroid forum. I have hyperthyroidism and my body temp goes crazy when it's not regulated right, also fatigue is symptom, as well as depression if you are under-active.Might want to see a endocrinologist.
When the body temperature fluctuates up and down like that, it is usually an indication that your body is fighting an infection. Could be a viral or bacterial infection.
If you suddenly felt worse after starting to take the Lexapro, it may be that you have an allergy to it.
Lexapro is an antidepressant and one of the side effects of antidepressants is drowsiness.
If your temperature is still fluctuating, it may be a good idea to see your doctor.
Best wishes.