It's not blood rushing away from your head, I should think it is just a complete rush of blood to your head for the brief moment you are in the whole 360 degree spin. Its totally normal, you may even find it wears off after more practice. I gather it is a new move and the stars you get are for a brief moment???
When I was a pairs-adagio ice-skater I got some dizzy starry moments! I used to get broken blood vessels in and around my eyes because of the pressure of certain spins where my head was lower than my legs and feet. I got used to it. Also the liquid in the inner ear bit has a part to play with balance and motion which can be upset but slowly gets used to the crazy angles we may regularly throw ourselves in.
This is all my thoughts from my experiences about stars and dizzy bits. More of a comfort talk really. If it gets worse, check your health and eating, breathing, blood pressure etc... all ok? Maybe consult a doctor with all this if you are really worried.
Good luck with your tricks! Sounds great!