It looks like you are looking for help with the passages which include the above three quotes. If so, let's discuss them below. Bolded words are mine.
Seyton!—I am sick at heart,
When I behold—Seyton, I say!—This push (battle offensive or war)
Will cheer me ever, or disseat me now (either I will reign or lose my power).
I have lived long enough. My way of life
Is fall'n into the sere, the yellow leaf, (fallen into the realm of old age; 'sere'- withered and aging; 'the yellow leaf' refers to the autumn of one's years, when one is approaching death (winter)
And that which should accompany old age,
As honor, love, obedience, troops of friends, (Macbeth says that he cannot hope to have all the desired things which should accompany his old age: honor, love, obedience (from subordinates), and a faithful group of friends).
I must not look to have, but, in their stead,
Curses, not loud but deep, mouth-honor, breath
Which the poor heart would fain deny and dare not. (Instead, Macbeth can only hope to have the surety of soft curses, honor from those who don't really mean it ('mouth-honor'), and a miserable life which lingers (he compares such an existence to a heart which despairs of life but is afraid to die. In other words, the heart is personified as a sentient element; here, Macbeth connects this personification to his own dread of the coming struggle. Interestingly, this speech foreshadows Macbeth's eventual defeat and his prophecy here proves prescient/prophetic as the play concludes).
Cure her of that.
Canst thou not minister to a mind diseased, (Macbeth wants to know why the doctor can't cure his wife's diseased mind or what appears to be a psychological ailment).
Pluck from the memory a rooted sorrow,
Raze out the written troubles of the brain(Macbeth thinks that all the doctor has to do is to pluck the offending trouble from his wife's memory, to 'raze' or to take out whatever worry is oppressing her).
And with some sweet oblivious antidote (Here, Macbeth thinks there's some drug which can accomplish the above purpose).
Cleanse the stuffed bosom of that perilous stuff
Which weighs upon the heart? (Macbeth thinks that his wife's spirit is merely burdened with negative emotions or 'perilous stuff,' whereas Lady Macbeth is actually inflamed with a powerful, ambitious spirit which her husband has failed to account for. Here, remember that in Shakespeare's time, the health of one's body was predicated on the balance of the four humors- blood, phlegm, yellow bile, and black bile. So, that 'perilous stuff' Lady Macbeth is burdened with is none other than the preeminence of yellow bile in her body, which lends her a choleric temperament.
In Act 1 Scene 5, in the famous Lady Macbeth soliloquy, Lady Macbeth has chosen to invoke the spirits 'That tend on mortal thoughts, unsex me here, And fill me from the crown to the toe top-full/Of direst cruelty.' In other words, she has chosen to burden herself with a spirit which will give full vent to her choleric cruelty. In imbuing her husband with this same spirit, she also condemns her husband to share her fate. His mind later becomes as deranged as hers. Consider the dagger hallucination soliloquy, and Macbeth's last words as he prepares to fight Macduff. He thinks he can't be harmed by a man born of woman and that he leads a 'charmed life').
She should have died hereafter. (She would have died eventually).
There would have been a time for such a word. (Such news as this would have been announced in due time).
Tomorrow, and tomorrow, and tomorrow,
Creeps in this petty pace from day to day
To the last syllable of recorded time,(Each tomorrow creeps along slowly until the end of time).
And all our yesterdays have lighted fools
The way to dusty death. Out, out, brief candle! (Every past day has only served to light the path of fools to their deaths).
Life’s but a walking shadow, a poor player
That struts and frets his hour upon the stage
And then is heard no more. It is a tale
Told by an idiot, full of sound and fury,
Signifying nothing. (Basically, Macbeth laments that life is often a waste of time, full of 'sound and fury' which eventually fades away, 'signifying nothing.' Here, in Act 5, Scene 5, Macbeth's words foreshadow the manner of his own death. He fights Macduff to the bitter end, in a clash of violent fury, but his efforts are futile and lead only to his death. He is beheaded by Macduff, and his violent ambition has turned to nothing).
Hope this helps. Good luck for your midterms!