Twins then Singleton

I had twins almost 6 years ago. Identical twin girls. I had no symptoms at all with them except the occasional heartburn and frequent urination with this pregnancy I am eight weeks and three days as far as I know with only one and I'm having a few symptoms already morning sickness and heartburn being number one. I know every pregnancy is different but can anyone tell me how a single pregnancy is different from twins and if it'll change when I am able to