Bruise with a lump....

I am 19 weeks pregnant with my second child. With my first pregnancy I had alot of health issues and had to quit working at the greenhouse I worked at very early in the pregnancy. This time I am working at a horse barn with Thoroughbred race-horses, breeding stock and riding horses.
On Wednesday one of the horses threw a tantrum and kicked me in the stomache. It hit about an inch to the side of my belly button but I twisted and bent as it hit so it caught all the muscles in my side too. I got checked by a doctor and the baby was fine and the kick missed the womb completly but the bruise on my side now has a lump in the centre of it.
It is right over the round ligament on my left side and I have to use my hands to support my belly when I stand or the muscles spasm so bad I can't move. I am starting to worry that the round ligament muscle might have torn a little or something. I have an ultrasound Thursday morning and am just wondering if I should have a doctor check it while I am in the hospital or if it is normal to have lumps like that in bad bruises.