Breakdown of Estoy harto porque el ruido me abruma.
estar
to be (location/state)
porque
because
el ruido
the noise
me
to me / me (direct object)
Questions & Answers about Estoy harto porque el ruido me abruma.
Since the lesson is about estar para for moods, could I use it here instead of estoy harto?
You cannot use estar para directly with the adjective harto, because estar para must be followed by a noun or an infinitive. However, to express a similar mood using the lesson's structure, you could say estoy para explotar (I am ready to explode). Estar harto is simply the standard adjective phrase for being fed up.
Why is estoy used here instead of soy?
What kind of pronoun is me in me abruma?
It is a direct object pronoun. The verb abrumar (to overwhelm) is transitive and acts directly on you. The noise (el ruido) is the subject performing the action, and you (me) are the direct receiver.
Why does porque trigger the indicative abruma instead of the subjunctive?
The conjunction porque takes the indicative when you are declaring a fact or the actual cause of an event. Since the noise overwhelming you is a stated reality that you are asserting to be true, the indicative mood is required.