Medical records given to family are copies. Go to your original doctors or better yet hospitals to get records. Find a doctor or nurse who can help you decipher them, as they wont make much sense in some cases. The only exception to lost records I can think of is the military, they tend to have one record that you carry with you when you transfer from one base to another, and if it gets lost your kinda S.O.L, though some of it is recorded somewhere as the army is good about doing forms in triplicate.
Get a copy of your original birth certificate. It will often have the name of the doctor that delivered you and that can come in handy when researching your records, as well as comparissons.