Who are you?

A well rounded friend,
Here to help you until the end.

Well if that's the case,
How much will you lend?

I'll lend you my all,
In the hopes you feel better.

Will you help me forever,
Let me cry into your sweater?

I'll try my hardest,
Try to steal all your pain.

Will you be the one
To make me feel sane?

When you have trouble with your brain,
I'll take it away.

Will you make it all okay,
Will you brighten my day?

We'll talk constantly,
Until you see more than just blue.

But what happens then,
Will the cycle renew?