I've had horrible m/s all day/night long since week 5! With my 1st child it was bad as well, but didn't start until the 8th week. Anyway, my husband and I went to the doctor last week to make sure I was okay and not too dehydrated and the midwife found twins on the ultrasound! She said that that is probably why it is worse this time around and started so early, cause twins dramatically increase your hormones.
We're definitely excited, but we need a bigger car! And house! lol.