Let's

[Shay]

While the intention of this is based on a beautiful emotion, I thought the execution of the concept on hand wasn't that effective at some places. 

So beautiful that I can hardly breathe.
Your smile bright like the sun. I want to stare, - This segment is rather abstract, the obvious linkage of sun/stare isn't evoking the emotion you were aiming for here (which is further undermined by the placement of "beautiful"). Yet, it's a decent approach towards descriptiveness. 
but can't. Your gaze piercing me like a scream,
reverberating through the air inside
my lungs, the blood within my veins, my soul. - I thought the initial outline here was very powerful and descriptive It's also nice that you're employing stylistic devices, however, the "piercing like a scream" is a rather common notion. A comparison could've been drawn in association with the preceding segment, sun/stare/ray for instance, to enhance the consistency. 
I'm hot and cold at once, and so alive,
awake, because you're better than a dream. - This is very nice, but I feel like it lacked some more detail, like, why is the person "better than a dream"? It appears to be slightly abrupt. 
I want to cocoon myself in your hair,
and tangle up our fingers, legs, and arms. - It has been pointed out already, but "cocoon" could be replaced by a word less powerful as you are descriptive enough in this segment, it's not as natural as the segment overall.
To brush my toes against your toes, to feel
your lips against my lips. Let's fall in love.
I promise it will be so wonderful. - The first two lines were nice in terms of imagery creation. the last line however, didn't feel like you were concluding that powerful, as "wonderful" is a quite vague reflection of "falling in love". 

Nice work overall, thanks for sharing.