Q1- What does the poet do to shrug off the painful thought of her mother's approaching end?

Q2- Why does the poet draw the image of "sprinting trees" and "merry children"?

1) ​Irrespective of a person's age, the yearning for home and the bond that one feels for their family never ceases to weaken. In fact, with age and growth these bonds become deeper as one moves away from home. The 'old familiar ache' refers to the pain of separation from family that we feel acutely when we are children. It also comes with a sense of fear emanating from a supposition that one might not meet them again for some reason. As the child grows up, the parents also grow older and we are all aware of the fact that death is inevitable. So as the poet leaves her mother behind, she feels that pain of separation from her mother and also a fear of never getting to meet her again if some unfortunate incident happens.

2) The poet draws the image of merry children and sprinting trees to iterate that the young must do as the old before them must have done, leave their parents in search of their own way of life. This cycle of young and old is eternal and the young should not stop living their lives because they have the old to take care of. They must remember that they owe their first allegiance to their own selves and then to everyone else, only then can they be happy and take care of others' needs.