You'll be fine. I have two cats and they climb on me and occasionally scratch me by accident and they've even stepped right on my tummy and I'm 21 weeks and baby is just fine.
I have three huge dogs that have scratched my belly and my son is fine. Your baby is fine :) but if your skin does break make sure to take the steps to clean it properly
If the dog broke skin make sure you keep it clean with peroxide and triple anti-anti-bitoic ointment. The problem with animals scratching you is transferable things. Same reason why you shouldn't clean a litter box while pregnant. Those same parasites can be on the cats paw after going to the bathroom. Then the cat scratches you and you can contract it. I wouldn't be too worried like I said just keep it clean. If it starts to show signs of infection I'd go in.
It won't hurt your baby if it's a scratch. How far along are you? I would worry if you gain any abnormal symptoms that you normally don't have. Like vaginal bleeding, early signs of labor, and depending on how far along you are; low or no fetal movement, etc.
Our dog is a German shepherd chow, (she's more than half my weight) and one day she was very excited when we got home from our errands. She jumped up on me, I caught her paws and attempted to lightly push her away from my belly, but she managed to get a nice scratch on me. It was a bit of a nudge, but my baby seemed fine and was moving about like normal. At one of my doctor appointments, the specialist had to nudge and jiggle my belly to get her to turn a bit. (Didn't work, has to go in 2 weeks later, lol.)
I would be extremely mad when the dog sctratched me but I guess thats why I don't have animals lol. But I heard someone say a cat scratched their stomach while pregnant but she didn't have trouble I don't think a scratch will be an issue but I think maybe rubbing achole on it so it will not get infected.