Rice Cereal

So I finally decided to give her rice cereal but now I'm regretting it. After about a week of rice cereal baby girl is a little stopped up. I've been reading online and I think I need to be giving her more water. I've been giving her a few sips after meals but now I'm thinking that I need to give her more. I also read that switching to oatmeal can help. I decided to re-introduce eggs into her diet. I hope that's not complicating things.