When i breath i feel like im not breathing in properly my nose is dry and i feel like my stomach is heavy. on accutane?

Usually it's congestion of the nasal membranes rather than dryness that causes impaired nasal breathing. Try irrigating your nasal membranes gently with clean warm salt water. If you're mouth breathing you may be swallowing too much air causing gas buildup in your abdomen. Drinking hot water would breakdown the gas enabling it to be passed through the intestinal tract and out the rectum.