You should have received two Form 1099-R's for the pension income in the year you turn 59 1/2.
One with a code of 2 in box 7 for when you were under age 59 1/2 and one with a code of 7 in box 7 when you were age 59 1/2 and older.
Contact your plan administrator and find out why you did not receive the correctly coded Form 1099-R.
