Open Question: how long does it take to recive a medical card by mail after being approved?

Im pregnant and my doctor said i have to have my medi cal card when i go next month in order for him to see me. I was approved on March 3, 2010, but i havent received the plastic card, i tried calling but none of their numbers work, and my social worker never calls me back, ive left messages should i worry? is it normal for the plastic card to take long to get here?