I Normally Take 159 Mg Of Effexor Twice Daily,and After

I normally take 159 mg of effexor twice daily,and after taking all my morning pills, I felt the effects of effexor withdrawl and began to feel real bad. I figured that I missed my effexor pills when i took all my morning medications so I took them again. I am concerned that i took them twice and am confused as to weather I should also take my normal evening dose aswell. If I do I will most likely have a total of 450mg of effexor innmy system for one day. What should i do?