What is the meaning of the phrase “can’t go on”?

The Quarrel

I quarreled with my brother

I don’t know what about,

One thing led to another

And somehow we fell out.

The start of it was slight,

The end of it was strong,

He said he was right,

I knew he was wrong!

What does the underlined phrase mean in this stanza?

What is the meaning of the word "charging up’’ in the following sentence?

Just as he trumpeted, he heard a loud crashing and stamping. A herd of wrinkled elephants came charging up.