twins?

Okay so I'm 9 weeks pregnant today with my second baby. My first pregnancy was 'easy' meaning little to no morning sickness or other general symptoms, I didn't even realize I was pregnant till almost 12 weeks. My son is now 18 months. With this pregnancy I have all of the general symptoms including horrible morning sickness I knew I was pregnant at week 4. I had an early positive test. I know every pregnancy is different, but I've had this feeling I'm having twins since I found out. Could it be? First US is on oct. 26th.