A more mainstream English word for "invoking Poe's Law"

I'm thinking of a definition like this:

v. Insincerely acting out or pretending at a set of actions and/or beliefs, often for comedic effect, with such vigor and frequency that the actions or beliefs become habitual and are eventually indistinguishable from one's sincere behavior

e.g. "I swear I was only doing it ironically, but people kept telling me I was ________"

The closest I can think of is "invoking Poe's Law", but Poe's Law is specific to the internet and I'm looking for a single word if possible.

Let me start by saying that I don't think invoking Poe's Law quite fits in your blank. You're not invoking the law, but you may be demonstrating or exhibiting or corroborating it.

The closest phrases I can think of that fit your situation are blending fact with fiction and can't tell what's real.

For example:

I swear I was only doing it ironically, but people kept telling me I was blending fact with fiction.

Unfortunately, blending fact with fiction is sometimes used to describe the process of mixing falsities into the telling of a true story. But understood in a different way, it clearly applies to your hypothetical person who does sarcastic and ironic bits so often and so seemlessly that others cannot tell what (of his) is sincere.

Or:

I swear I was only doing it ironically, but people kept telling me they couldn't tell what was real.

The phrase can't tell what's real is rather common, and it perfectly describes your hypothetical audience.

"I swear I was only doing it ironically, but people kept telling me I was becoming it."

Become — ODO

verb 1.1 Grow to be; develop into

Or, turn out to be

Related quotes:

"Be careful of your thoughts, for your thoughts become your words. Be careful of your words, for your words become your actions. Be careful of your actions, for your actions become your habits. Be careful of your habits, for your habits become your character. Be careful of your character, for your character becomes your destiny.

"The mind is everything. What you think about, you become." - Buddha
"You become what you think about all day long." ― Ralph Waldo Emerson
“Beware that, when fighting monsters, you yourself do not become a monster... for when you gaze long into the abyss. The abyss gazes also into you.” - Friedrich Nietzsche