Like walls around me

Your arms were like walls around me.
So now you left, just to let make me feel
how loner this space can be?
Please don't leave me hanging on.
Remember the things we could become,
but we never will be.
You just didn't need me.
And I try to understand but I can't.
And the hardest thing is, that I can't tell you
how much I love you,
how much I need you,
how much I care.
But you can't be here, you're not here.