Is it possible to get nausea and dizzieness (morning sickness) a week or so before missed period? Not sure when I ovulate or is it caused by my gerd?

Both. Symptoms of pregnancy usually begins around 5-6 weeks of pregnancy. It is more likely that those symptoms are due to other causes. Occasionally women might be more far a long in their pregnancy that they think and in this event they can experience symptoms of pregnancy "early".