What is Hamlet most upset about according to the passage below?

Oh, that this too, too sullied flesh would melt,
Thaw, and resolve itself into a dew,
Or that the Everlasting had not fixed
His canon 'gainst self-slaughter! O God, God!
How weary, stale, flat, and unprofitable
Seem to me all the uses of this world!
Fie on ’t, ah fie! 'Tis an unweeded garden
That grows to seed. Things rank and gross in nature
Possess it merely. That it should come to this.
But two months dead—nay, not so much, not two.
So excellent a king, that was to this
Hyperion to a satyr. So loving to my mother
That he might not beteem the winds of heaven
Visit her face too roughly.—Heaven and earth,
Must I remember? Why, she would hang on him
As if increase of appetite had grown
By what it fed on, and yet, within a month—
Let me not think on ’t. Frailty, thy name is woman!—
A little month, or ere those shoes were old
With which she followed my poor father’s body,
Like Niobe, all tears. Why she, even she—
O God, a beast that wants discourse of reason
Would have mourned longer!—married with my
uncle,
My father’s brother, but no more like my father
Than I to Hercules. Within a month,
Ere yet the salt of most unrighteous tears
Had left the flushing in her gallèd eyes,
She married. O most wicked speed, to post
With such dexterity to incestuous sheets!
It is not nor it cannot come to good,
But break, my heart, for I must hold my tongue.