should i assume that the fact that my birth certificate, medical report etc are in that "DO NOT OPEN" package i gave to DHS when i arrive i won't need to provide these when filing for AOS??????

You will not need any of the medical information from the envelope you gave at the POE, but you will require a Vaccination Supplement, which can be prepared by a Civil Surgeon in the U.S. If you have a copy of the Vaccination Worksheet from your medical exam in your home country, then the civil surgeon can just transfer the information from the worksheet onto the supplement.

I can't remember if you need your birth certificate for the AOS process or not, but you didn't give them your only original did you? You should always only send copies of documents and then take your originals with you to show them at your interview. If you give them originals, they will keep the originals.