Hello, how long have you had the problem?
Have you had any tests?
What dose of omeprazole do you take? How long for?
Do you take any other medication?
Any other symptoms?
Does the world feel like it is moving around you?
Any problems with your gait?
Tell me about the pattern of numbness and tingling?
Have you had any viruses or other infections recently?
Thanks for the extra information. The first thing is to have a neurological examination to ensure that the numbness and tingling and imbalance problems are not related. Very rarely a post viral condition can cause a problem like this. It will also clarify if there is an underlying vestibular problem, that means whether there is a problem with the inner ear causing the imbalance and that in itself can cause nausea.
The fact that the nausea gets better once you are upright might be linked to a positional vertigo.
However it is entirely possible that the nausea is related to a reflux issue, and the omeprazole should help with that although it is still early days. I would suggest taking the omeprazole at bedtime and raising the head of the bed slightly to see if that improves matters.
Do avoid alcohol and try not to eat a heavy meal too late at night.
So make an appointment after the holiday weekend for a full examination.