Habd you talked to your doctor about this? Drywall is TERRIBLE FOR YOU TO EAT!!!! My boyfriend used to hang drywall and just him hanging it and being around it was terrible for his lungs(and the other workers) I couldn't imagine eating it!!!!! You need to talk to your doctor!!!!! Like NOW!!!!! Good luck I hope baby is fine along with you as we'll!
Honey, you need better prenatal vitamins, you're craving minerals if you were willing to eat something that normally unappetizing. Talk to your doctor and give him or her an idea of the frequency or the amount you ate, and go from there. You're probably fine, and the doctor has doubtless heard of pregnancy pica before, so don't be embarrassed, just tell and see what advice he or she has for you.