I haven't taken my naproxen in a couple of day and now have a headache and feel nauseated is this withdrawal?

Not naproxen: Naproxen is not a medication that you get withdrawal from if you stop using it. I'm not sure what the causes of those symptoms is but it is not due to stopping naproxen.

Possibly: Withdrawal symptoms usually do not happen with Naproxen and nsaids, however each person is different. If you have been using Naproxen regularly you might have symptoms when you stop taking it. Nsaids should be used for the shortest amount of time possible, at the lowest effective dose.

Possible: The nonsteriodal class (including ibuprofen) can cause "rebound headaches" after cessation, if they were being taken on a consistent basis. If headaches persist or new neurological symptoms occur, would contact your primary physician.

Yes: Agree with dr. D. If you've been taking Naproxen regularly, you can have withdrawal headaches. Naproxen and the nonsteroidal anti-inflammatory family are least likely to cause rebound headaches but still can. [most likely: opiates, butalbital, aspirin/apap/caffeine. Medium likely: triptans like imitrex]. Talk with your doc if this continues or gets worse. Be well.