Hope this helps. Lady Macbeth may actually faint in astonishment that her husband has killed the guards in an act that was not part of their plan in murdering Duncan. She could be shocked that he has acted so boldly when she had to question his manhood in order to provoke him to kill the king. On the other hand, she may be faking.
A) The positive action that the poet toke to change her circumstance is in line 5, the poet states that they "learned to love each day".
B) In line 2 the poet refers to Laughter as "delicious inside." Meaning it felt good to her but not as an external feeling but as a internal feeling.
C) Life is referred to as a seed in the poem (see Line 8) because seed are given off of a plant that has reached it maximum maturity and wants to spread or renew itself. Life is like this in some ways, Life makes you feel like you can go anywhere until you come to a realization or a a turning point in which you are reborn or changed.