back to birth weight!

My baby boy had his first pediatrician appointment today, and he's already back to his birth weight of 6lbs 3oz at only 5 days old! I say technically 4 because his first "day" was 9 mins! It's such a relief because he is such a peanut and was born before his due date...only a few days, but still! with my first she lost 10% of her birth weight at the hospital... and didn't gain it back until she was 11 days old! Plus she was so much bigger than he is, she was a week late and 7 1/2 lbs