There should be no shrinkage of the composite material after it has been completed in the office. When the bonding is placed there is slight shrinkage that is accounted for by the dentist. The material should be stable when you leave the office. It is possible that a piece may have dislodged but...
You have a great looking smile. Some minor shaping of the central incisors and canines will be magical in your case, as this will give the a much closer mirror image of symmetry to the left and right side of the smile.This is done without any need for local numbing injections and when done...
Your teeth really shouldn't hit. It sounds like having a simple adjustment on your retainer would probably solve the problem. Call for an appointment and they should be able to do it quite quickly and easily