Does effexor have negative side effects if you forget to take it? i forgot to take my 75mg last night and 75mg this morning so i took it this afternoon but i feel very out of it. i can't stand up without feeling dizzy and nauseous and my brain feels like

Yes, : Yes, this is a well know issue with effexor (venlafaxine). What is referred to as discontinuation syndrome can occur when one or more doses is missed. Discontinuation symptoms can include: difficulty concentrating, shaking, sweating, headaches, nausea, "brain zaps", irritability, anxiety, depressed moods, hearing things and increased blood pressure. If you miss a dose, take the next one at your next regularly scheduled time. Don't double up on doses to try to catch up. Since I am answerig this 3 days after you asked, you should definately be feeling better by now.

Yes, it is usual: Just take your daily dose and continue a regular scheduled plan as usual.