I've been vaping for 9 days and I was light headed for about the first 2 days. It was worse when I would smoke an analog so I stopped smoking them. I figured it was too high a nicotine intake so I slowed down my nic intake to 3 mL a day of med (12 mg) juice. I had smoked 2 packs of Marlboro Lights per day for 20 years. The dizziness went away, unless I get new flavors in and begin chain-vaping.
I was also irratable, I mean really bad tempered

, for about 3-4 days. I still feel the irritation but I had to psychologically come to grips with the fact that people are idiots and do really dumb crap 8-o. I had to learn to take a deep breath before I react and just be more understanding of everyone elses inadequacies. I know this sounds like I'm full of myself but, this has worked and people don't threaten me with physical violence as often.
Stick with it, it will all be worth it once you completely get over the analogues.