Must apologise that I haven't been able to comment your poems lately. Taking an hour from my schedule to catch up with people's poems.

'Walking on the interstate
The rush of cars is on the air
I'm barely keeping my feet on the ground
But I just can't seem to care'

Okay so we've established scene; yet I don't know what you mean by 'rush of cars is on the air', use the language to open up your descriptions. Not keen on that rhyme much, it's cliche like the 'put your hands in the air like you just don't care!' lol.

'I wonder what would happen
If I took one more step to the right
Plunged to the ground and cars rushing below
Instead of running from another sleepless night.'

So now we have meaning - the persona is suicidal or contemplating it? The third line didn't have the impact I think you wanted it to. 'Another sleepless night'; this is a bit out of nowhere.

'The doctor gave me pills to take for that
Each night before I go to bed
But lately I sweep them under the rug
Because they disturb the thoughts in my head'

Hahaha, are you writing this about me?

'Makes me wonder who I am -
If I want to be that one
So to rediscover myself
I took a walk under the radiant sun.'

Second line: be that who?
Liked the motive of the persona, it's clear.

'And even though I didn't really find
What it was I was looking for.
As the sunlight faded away
My thoughts were running pure.'

Far too many 'I's in this piece, there's no way of you letting the reader in here, so there's not much to go on. Nice image here though.

'So instead of running hard
I'll slow to a steady pace.
Count the stars hanging in the sky
Instead of trying to remember his face.'

Whoa - what? 'his face'? This was completely out of the blue and a bit of a jump in tone, please don't throw in a boy character hahaha.

'After all, it doesn't matter
When he left me or even why
As long as they keep handing out medication
Rest assured; I'll be fine.'

Too late! Haha. Bit of a strange ending, though I liked the last two lines, can't say I liked the first two though.