Why should this change of thoughts

Pericles
Why should this change of thoughts,
The sad companion dull-eyed Melancholy,
Be my so used a guest as not an hour
In the day’s glorious walk or peaceful night,
The tomb where grief should sleep, can breed me quiet?

And what was first but fear what might be done
Grows elder now, and cares it be not done.

Here pleasures court mine eyes, and mine eyes shun them;
And danger, which I feared, is at Antioch,
Whose arm seems far too short to hit me here.
Yet neither pleasure’s art can joy my spirits,
Nor yet the other’s distance comfort me.
Then it is thus: the passions of the mind
That have their first conception by misdread
Have after-nourishment and life by care;
And what was first but fear what might be done
Grows elder now, and cares it be not done.
And so with me. The great Antiochus,
’Gainst whom I am too little to contend,
Since he’s so great can make his will his act,
Will think me speaking though I swear to silence;
Nor boots it me to say I honor him
If he suspect I may dishonor him.
And what may make him blush in being known,
He’ll stop the course by which it might be known.
With hostile forces he’ll o’er-spread the land,
And with th’ ostent of war will look so huge
Amazement shall drive courage from the state,
Our men be vanquished ere they do resist,
And subjects punished that ne’er thought offense;
Which care of them, not pity of myself,
Who am no more but as the tops of trees
Which fence the roots they grow by and defend them,
Makes both my body pine and soul to languish
And punish that before that he would punish.