If u see the gynae too early u might not be able to see anything on the ultrasound. 4-5weeks is only a tiny dot, but if u really want to do it, still can la. At week 6, it's a small lil "prawn". Anyway if it bothers u so much u can always walk in to KKH 24hrs O&g clinic at B1 or TMC emergency to check. They have ultrasound equipments there.
Yve Loh