cold turkey?

I was on 75mg of venlafaxine for over 2 years and about a month ago increased it to 150mg as I was depressed due to family illness and traumas (my Dr recommended this). But I felt awful and had lots of side effects so I have dropped back down to 75mg suddenly about 4 days ago. and have only been taking 75mg for the last 4 days. Felt fine until today but I've got the shakes, churning upset tummy, feel lightheaded and really panicky. I know this is the tablets but I don't know how long this will last for does anyone else know? feel horrible and cannot wait to feel back to normal again, Nicola :wacko: :scared15: