Hiya! Yes that's normal and it means you're getting good exercise! Hooping really makes your body work. After you have been practicing for a while your stomach muscles will kick in and you won't need to move your body so much. to begin with the movement (rocking the hips forward and back) needs to be really exagerated - with practice you'll make it look effortless.
Keep practicing, keep laughing at yourself, keep picking up the hoop and KEEP BREATHING!
Sal.