The gluten free and corn pizza crusts just arent the same. Can I have regular pizza once a week if celiac?

Avoid ALL gluten. With celiac disease, exposure of the intestine to any gluten causes inflammation of affected gut lining, with a decrease in absorptive surface of that gut, & resulting malabsorption of food. The best & most enduring fix is to avoid eating any gluten. Serum tissue transglutaminase antibody can help determine how successfully gluten is avoided. Don't compromise your health for taste preference.
We have to say NO. But it's your life & your gut so it's your call. Do you remember how you felt before you eliminated gluten from your diet? You improved by avoiding these foods. An occasional indiscretion will probably not take you all the way back to full-blown celiac disease but it will certainly do some damage. Moreover, recovery will take much longer than the enjoyment of that slice of pizza. Choose wisely.