Hello, Cough can be due to the pressure of the enlarged thyroid on the trachea as well as due to some other cause like chronic sinusitis with postnasal drip, reflux, infection and so on. This should be ascertained by a physician separately. Vomiting may be related to the gastritis of pregnancy and the presence of brown blood suggests some collection in the stomach. Gastroscopy may be done with ample care to locate the exact cause and to help plan further management. Simple gastritis can be treated with antacids, anti-emetics, bland diet and small frequent meals. Your thyroid anomaly also should be attended to. Hope this helps.