komatsugrader155

Hi guys iam new to the site and new to bmw,i have a 530d se auto 2004.The other day i stoped at my mates to show him my new car,and on the way home i put my foot to the floor and she droped down a gear but woundent go over 4000 revs.when i got home i let the car sit for ten minutes or so and went for a drive and she was fine, have i anything to worry about, can anyone help please.