 [ Symptoms ] why do i feel lightheaded fatigued and sweat during sleeping no fever  i am an almost 37 yr old female with a lot of stress right now dr put me on effexor and i started not being able to sleep having bad headaches feeling lightheaded and constipated i took it for 2 weeks and he told me to stop when i called him he called me in something else but i am afraid to get it i have been on paxil prozac and celexa and never felt this horrible i have not taken anything in almost a week but feel lightheaded many times thoughout the day any ideas what could be wrong [ Disease ] i am not sure i also have been having severe night sweats body feeling hot then chilled flushing in the facial area and neck i spoke w my doctors they cannot seem to figure it out could be possibly meds you are taking anxiety and stress infection of some kind that is what was told to me i was given a blood test to check my thyroid everything ok you might want to get your thyroid checked through a blood test i hope that this helps in anyway i know what you are going through