One baby or two???

So from about 9weeks I was able to find my baby’s heartbeat on the right side of my uterus well this morning I’m almost 11weeks along and I was able to hear baby’s heartbeat on the right and left side of my uterus. Somewhat close together but still a heartbeat on each side. My dr called me the other day and said that everything was in “normal” range for blood work. My first ultrasound is on Tuesday but could it be twins if I hear a heartbeat on the right and left side?