After childbirth, when i am in a car, i cant move my head any side, or see my mob's screen. otherwise i have terrible feeling of nausea and giddiness.

Headaches??: When you walk or change positions do you also have this feeling? if so, please see you primary. They may evaluate you with a brain imaging study, blood work and/or refer you to an ENT specialist. It could just be hormones correcting themselves, volume loss etc. In office, your primary may be able to perform a simple test, called Dix Hallpike to determine if you have positional vertigo.