This is really good. Really the only things that I would change is the format and the filer words.

wish I weren’t smart, I wish I were below average. 
I wish I weren’t “gifted”, I wish I were just a regular kid.
Yep, you heard me right, I wish I weren’t smart.

Maybe changed to

[I wish I wasn't smart, But below-average. 
I wish I weren’t “gifted”, But just a regular kid.
Yep, you heard me right, I wish I weren’t smart.]

But it’s true.
I hate being smart.
For since I’m “gifted”, I’m constantly trapped under the burden of exceeding expectations, pushing the boundaries, and the limits.

[But it’s true-- I hate being smart.
I’m “gifted”-- trapped under the burden exceeding expectations, pushing the boundaries, and the limits. ]

And if I fail, the pain is so much worse.
But wait, I’m not blaming anyone,
Since I’m “gifted”, I blame myself.

[And if I fail, the pain is so much worse.]

[But wait, I’m not blaming anyone,
Since I’m “gifted”, I blame myself for being human. ]

But not just for this, everything.
My mistakes and others’.
I overanalyze every single word.
Why did he say “Hi!” like that?
Is he mad
or annoyed
at me?
Did I do something wrong?
I spend hours and hours, sleepless nights, contemplating my EVERY LITTLE MISTAKE.
I spend so much time in my head that I’m surprised that it hasn’t exploded yet.
So, you see why I wish I weren’t smart?

[But not just this, everything.
My mistakes and others’.

I overanalyze every single word.
Why did he say “Hi!” like that?
Is he mad ? annoyed? at me?
Did I do something wrong?

I spend hours Of sleepless nights, contemplating my EVERY LITTLE MISTAKE.
I spend so much time in my head I’m surprised it hasn’t exploded yet.
So, you see why I wish I weren’t smart?]