What Causes Dizziness, Tingling Sensation In Finger And Toes?

here are my symptoms - im 33 yrs old female- dizziness when sitting or standing, feeling of faintness the longer i try and stand. have had tingling in fingers and toes. right arm tingled and felt havey for @ 4 days. blood preesure has been about 106.80 since this began...which is low for me. am unable to drive or walk for long periods, esp. in stores due to visual disturbances. words and sentences do not come out the way i want them...seem to get mixed up. i feeling of pressure in head. mri of brain normal - mri of neck - normal. saw an otgylosit prescribed steriod pak - clonoazepm and diuretic...seem worse now...any new ideas to try?? family is wondering if i should see a vascular or circulation doctor also b/c my hands and feet get very cold and pruple tinted..