Metallic taste in mouth feel weak nauseous, 2 neg pregnant tests, normal period. Can it be a flu, or body adjusting to birth control? Started 2nd pack

Could be. Certainly some medications may (birth control in your case) cause a metallic taste, as can viruses or bacteria that may cause infections. Usually, the body will adjust to the medication and the metallic taste will go away eventually. If the condition continues, seek medical evaluation. Good luck.