"Sick and tired" is a phrase that is commonly used for expressing frustration and exhaustion. However, instead of using this phrase repeatedly, it is good to have a diverse range of synonyms in your language. Some of the alternatives to "sick and tired" are "fed up," "exhausted," "weary," "disenchanted," "disappointed," "disgusted," "disheartened," "angry," "irritated," "annoyed," and "displeased." While all words can be used interchangeably, the choice ultimately depends on the intensity of emotions you want to convey. In a professional setting, using polite tones is advised. However, in casual conversations or when you are venting out, you can use stronger words to express your sentiments.