Thanks for posting your question here, I will try to answer it to the best of my abilities.Nausea
and light headedness is a rather common side effect of contraceptive
pills, as such it is entirely possible that they are the reason you are feeling this way.
Stop taking them for a week and see if your condition improves, if it does we've identified the cause. If it doesnt, see a doctor so that he can run some tests and try to identify the cause of your problems.
I hope this answered your question.