Quoting Trisa Daniel:" Twins don't happen from more than one sperm fertilizing one egg. Bloating, large sore boobs and peeing a lot are normal first trimester symptoms."
this..........Fraternal twins 2 eggs and 2 sperm (one sperm per egg)
Identical twins 1 egg 1 sperm then it splits and makes 2 zygotes after the egg has already been fertilized.
With my fraternal twins the only symptoms I had were extreme tiredness, morning sickness, sore boobs. But I had the same symptoms with my singleton pregnancies also.