If something is weighing on your mind, however trivial it may seem to you, it is not too unimportant to share with a counsellor. If something is bothering you, blocking you, preventing you from making the most of your life, then it is important. On the contrary, it takes courage to realise and admit you have a problem or difficulty. It is a sign of strength and intelligence to seek outside help to resolve a problem when you have reached a dead end through your own efforts. However no concern is too trivial or too serious.
People consult a counsellor for many reasons.
Other more general concerns centre around academic work, exams or finance, or feeling that it is hard to cope. This depends on the style of the counsellor. Generally, the counsellor will work with whatever issue you bring to the session. The methods used will be decided between you, but the overall aim is to help you resolve the issue which is troubling you. This is your right and your counsellor will understand and accept it.