Effexor is HELL to come off for some people. It will take a fair few weeks for your brain chemicals to sort their **** out. I will never ever ever go on that class of drugs again. The withdrawls from that was like NOTHING I have ever been through before, nothing like normal SSRI withdrawls. It is tough, really really tough. Hold on, it will pass after a while, then you just have the normal BP to worry about... but honestly that is better than Effexor withdrawls, so it does get better.