Aiyoh sayang, please go see your doctor or midwife asap, esp kalau sakit tu intense dan berulang macam ni, better safe than sorry at 33 weeks! Could be false contractions (Braxton Hicks) or gas, tapi only doctor boleh check properly dan confirm semua ok dengan baby. Jangan tunggu lagi, call clinic or clinic or hospital hari ni ye. All the best!