I use to get headaches and dizzy in the morning long time ago. It was caused by over hitting the vaporizer, in simpler terms
vaping too much and my body got a nic rush.
vaping isn't like ciggys with that "Ahhhh" after the first puff, the nic has to absorb into your system via mouth and lungs and that takes time. If your using a high nic juice (18 or 24), power hitting then a headache could happen, with dizziness then don't pull off your vaporizer like a cig, you don't have to pull hard at all to get a vape just let the vapor flow.
I found this how to vape explanation a while back and just reposting it:
How to vape...
Vaping does not use the same technique as taking a pull on a cigarette. Slow and gentle draws is key.
1.Take your index finger and place it against your open lips.
2.Close your lips around your finger to create a seal.
3.Begin to suck gently.
4.When you feel the vacuum on your finger, this is how hard you should pull when taking a vape.
5.To maximise nicotine absorption, hold the vapour in your mouth for a couple of seconds before exhaling/taking the vapour down into your lungs. Nicotine will be absorbed via the mucous membranes in your mouth (via cheeks/gums).
6.Remember that you will need to vape for a longer period than you would with a cigarette. The ten quick draws you would have with a cigarette is unlikely to satisfy when starting to vape.
7.Anytime you want a cigarette, vape instead. If after five or ten minutes of vaping you still want a cigarette, have one.
8.Transitioning may take some time. Don't worry about this; it's every cigarette you don't smoke that matters, not every one you do.