Here's a breakdown:
* Piensas: This is the second-person singular present indicative form of the verb "pensar" (to think).
* estoy: This is the first-person singular present indicative form of the verb "estar" (to be).
* siempre: This means "always."
* preocupada: This is the feminine past participle of "preocupar" (to worry) and is being used as an adjective.
* profesora: This means "professor" and is used to address the person the speaker is talking to.
The sentence implies that the speaker feels the professor thinks they are constantly anxious or worried.