I is a subject pronoun and thus serves as the subject of a clause:
I hit the punching bag.
Me is an object pronoun, which receives the action of a verb or serves as an object of a preposition:
My sister hit me. (direct object)
A small part of me wishes she hadn’t left. (object of preposition)
Myself functions as either a reflexive pronoun or an intensive pronoun.
In the mornings, I make sure sure to wash myself. (The object of the verb refers back to the subject of the sentence)
I myself disagree with the findings. (The pronoun myself looks back to the subject I to add emphasis).
Still confused by me, myself, and I? Check out the video below.