Hello and welcome to the board.
Many children (even non preemies) exhibit many of these same things in large situations. My oldest son has trouble with large group situations in that it makes him more excitable and overwhelemed. He does much much better in smaller situations.
For some children OT therapy does help, others just need time and maturity to learn to be better able to control themselves. For my son, this has meant searching out smaller daycare settings, in fact he is in a private home to reduce the number of kids he has to interact with, and a smaller preschool setting. As he has gotten older he is better capable of expressing himself in a positive manner and to handle larger situations like holidays.
You might look into reading the Out of Sync Child which is a book that talks about children with SI issues.
Moderator - First Time Moms, Parents of Preemies
Missouri State Coordinator
Mommy to Alex (4)and Mason (1 1/2)
Law Student - 1 year done, 2 to go