When someone says their mind is "clouded with thoughts of someone," they are expressing that their thoughts and emotions are heavily preoccupied with that particular person. The phrase "clouded with thoughts" implies that the person's mind is filled or obscured by these thoughts, making it challenging to think clearly or focus on other things.
In this context, the person's thoughts about the individual they are referring to might be constant, persistent, and overwhelming. It suggests that they are preoccupied with memories, emotions, or concerns related to that person, and these thoughts may be interfering with their ability to concentrate on other tasks or aspects of their life.
Typically, this expression is used when someone is infatuated with or deeply in love with someone, going through a difficult breakup, missing someone intensely, or experiencing strong emotions associated with that person. It can also apply in situations where someone is worried or troubled about the actions or well-being of the person in question. In any case, the phrase conveys the idea that the person's thoughts are dominated by their feelings and concerns for that particular individual.