your right :))) I'm sick = انا مريض I'm tired = انا تَعبان

مريض is the correct word. There are other words but not often used like سقيم ، عليل

formal way you say مريض,سقيم ، عليل(ex:if you read a book or write a formal latter) informal way you can say انا عيان او تعبان اومريض (ex. if you talk with your family or frinds)

أنا لست بحال جيدة = I'm not in good condition أشعر بتعب = I feel tired أنا متعب = I'm tired

u can say انا عيان او تعبان