Clysta is right...maybe your dates were wrong. As for your doctor blowing you off, I'd find another doctor next time for sure. You want someone who cares about you and what you're going through, not just someone who wants to get the money from the insurance company. God bless you and good luck :)
Oh honey im sorry to hear that. But yeah at 4 weeks its very very tiny.
Being that you were so early on, I don't believe you actually pass anything similar to that. Mostly it would resemble a period. At 4 weeks of pregnancy, baby is the size of a period at the end of a sentence. At around 9 weeks it would be around an inch in size. Are you sure of your dates?