Hello Friend, good story of common experiences in families.
That feeling of the parents when the children leave, is very powerful, but specifically that of the mother is very complicated to understand, certainly the fear caused is the uncertainty of what will happen to the child, the inability to be with him to to make the best decision, or simply to feel that it will no longer be your little one that depends on it, it is your fear or better a terror that you feel and there are no words or advice that can make you understand what is necessary and the best is that new path that the son will take; only the word of his own son, as the story indicates, can soothe that feeling of anguish.