Sayang, pain di area ari-ari and pinggang at 35 weeks ni perlu check with your doctor or midwife ASAP, okay? Jangan tunggu, better to go to the hospital or clinic now and let them assess, just to be safe for you and baby. A few of us mummy friends pun pernah experience cramping macam tu near the end, but some turned out okay and some needed monitoring. Better don't take chances, especially if the pain is really intense. Go see your doc today, yes? Sending you hugs!