Hello! Had she had a discharge? they don't usually swell until they have been in heat for a week or so. The females I have had that were not spayed really didn't have a change of attitude.They did swell quite a bit, and had a bloody discharge. They did hump each other alot, while one of them was in heat. It seemed that they had to pee a little more than usual, no changes in their health.
It didn't affect their pooping at all. But, of course all dogs-like people are different.Eleven months is not early,going in heat.
If she IS in heat-do not let her outside alone. You would be surprised to see how male dogs can find a way to get to her!