if im weening off effexor xr 75 mg i skip every other day can it cause faintingp

hi i been on effexor xr 75 mg for 8 mos now im weening off i told my dr i wanted off he sent me to a psychiatrist cause i was going nuts but part of the reason for that was my thyriod was very high it was 8.45 well im taking zoloft to help with the withdrawls i guess well in sept i fainted at the dr's on christmas and 2 days after i fainted again .then jan i fainted 4 times does this sound like something effexor would be doing my psychiatrist thought it was the zoloft but i told him i am having no side effects with zoloft but effexor i cant stand and cant wait for it to be out of my body its a hard drug to come off of thats the only withdrawl (withdrawal) symton im having so far just the fainting all along i think it was my thyriod but my gp dr never checked for that my psychiatrish did and found it.i skip my effexor every other day for 4 weeks then stop .any advice does anyone know about fainting spells on meds.