As Julz said, as long as she shows emotion and interacts normally around your and your husband then things are probably fine.
When you are in different surroundings or there are different people around just reassure her that you are there and if she wants to just sit on your lap or stand by you for the first hour or however long then let her. When she is ready (and probably older more than now) she will go play with others. Don't force her to do somethign she is not comfortable with as that will only make it worse.
My mother says that when my older brother was born (her first child - she was only about 23) she did evreything by the book cos she didn't know what she was doing. So when they said feed him, she did, when they said leave him to cry, she did. Exactly as the book says. Today he is the most insecure and reserved of us all.
With my younger brother however (her 3rd child - she was 32) she decided "stuff the books" she had mother's instinct and she was going to do as her gut told her. So when he got invited to birthday parties at 6 or 7 years old and was too shy/nervous to go alone she went with him, regardless of the fact that she was the only other mother there. When he was unsure of something, she reassured him and she never ever forced him to do something he didn't feel comfortable doing. Today (he's just turned 24) he is the most confident and outgoing of all of us.
So basically love your baby and let them know they are safe and go with your gut!