What Are The Withdrawal Side Effects Of Venlafacine?

What are the side effects if you stop taking VENLAFAXINE HCL ER 37.5mg cap cold? I take it 2xday. (EFFEXOR xlt). I am having dizzie spels when I lay down or get up. Have had 3 major surgeries on my back in less than a month. Lots of spinal fluid was lost. Some of my symptoms are the same since I stopped VENLAFAXINE cold turkey. The surgeries were Oct., Nov. of 2013. Have not called the DR yet but is on list of things to do today.