 [ Symptoms ] does keeping birth control in your checked luggage on a plane affect its effectivness [ Disease ] i can certainly see your concern however since your pregnancy test was negative it is unlikely that you are pregnant i would recommend that you see your doctor just to make sure since you are having symptoms of being pregnant your doctor may also do some bloodwork including a thyroid test to see why you may be having the unusual menstrual cycles and the other symptoms which you are experiencing