As with any other wedding detail you don’t have to do anything you don’t want to do, but you may feel awkward walking down the aisle without something to occupy your hands. Have you noticed that Kate Middleton always carries a clutch? I read it’s so that she always has a place to put her hands. Some sort of royal style tip.
Bridal bouquets come in all sorts of shapes and sizes so if you are trying to avoid a large cascading or round bouquet you can carry a posy (small, tight bouquet) or a single flower with a long stem like a calla lily.
You can talk to your florist about carrying smaller flowers such as lily of the valley which won't weigh much and can make a very romantic and lovely looking small bouquet. Click through bridal bouquet galleries on wedding planning sites to get ideas and talk to your florist about your concerns. He or she will be able to help you find the perfect style for you, your dress and your wedding.