I have been taking omeprazole for several years now. My last prescription, same 40 mg as previous ones, was different in color (brown & pink). From the information I found on-line, I concluded that it was a slow-released kind and safe to take. However, since I began ingesting this latest pill (May 13), I have begun to feel quite nauseated and light-headed a good part of the day. Next step should be? Thanks!