Best Friends?

You tell me I'm your very best friend,
That you feel closest to me more than anyone,
I thought that best friends confide in one another,
When the other one is down,
Their best friend is always around.
Obviously this just isn't the case,
And it feels I'm always the last to know.
I have problems of my own and I don't enjoy being a burden,
I try to keep myself to myself,
But there is only a certain amount of time that I can lie to myself,
And act like my life is OK with my fake smiles.
Maybe I've done something wrong,
Maybe you feel that I'm not always around,
But if you say I'm your best friend,
Then why am I not the person to wipe your eyes?
Why am I not your shoulder to cry on?
I feel like I'm not good enough for you,
And it hurts inside.
If we're "best friends" like you say we are,
Why does it seem we're slowly falling apart?