If you had a friend that pretended to be someone else online and asked you all kinds of personal questions but you find out it's your friend

Assuming they did it knowing it was me and deceiving me on purpose I’d be hurt that they felt they couldn’t just ask me as a friend. I’d feel like the only reason they did it is because they either don’t trust me or they were looking for a way to hurt me.

First, they're not a friend.
Second, start acting like you were someone acting like you and lay a line of crap about the friend being a real POS etc. Then just stop texting and see what goes on

Lol. It' would have to be proven for real and not just suspicion. And assuming they even knew it was you.
Wouldn't be the end of the world, lol.. But I'd confront them.

It would be a shocker when you discovered the secret. Then speaking to them in person would not go well

Definitely rethink the relationship

I'd be worried.

That would be fucking weird. Like, why is someone who presumably knows me asking me all this personal stuff? And why are they doing it anonymously? If you're really my friend, AMA.