 [ 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 ] thanks actually i had some bloodwork done and my vitamin d level was very low 7 i was put on 50 000 iu of a prescription vitamin d for 8 wks 1 a wk it is been 9 weeks tomorrow and now i am taking over the counter vitamin d am going back to dr next week to have blood checked again i felt better after the first 2 wks not dizzy not tired no more headaches then again i began feeling dizzy lightheaded alot and tired no energy i do not know what is going on but i will hopefully find out <positive_smiley>