My son's pediatrician discovered today that he has a slight heart murmur. He said it's pretty common…

My son's pediatrician discovered today that he has a slight heart murmur. He said it's pretty common and that right now he isn't really concerned. For now he is just going to keep an eye on it and if it doesn't go away then he will send us to a cardiologist. He said not to worry, but I am kind of freaking out now. Has anyone else gone through this? He is 5 weeks old.