Your reaction may be how you feel about new things that have been arriving in your life recently or that are about to. Surprises, unexpected things that happen, surprise visits, gifts, or parcels. It could simply mean that you are anxious about something that should be arriving in the mail, like a letter or tax information.
See Arrive, Give, Receive, End, Beginnings, Late, Delivery, Discipline, Responsibility, Time, Surprise, Visit.