Hmm, sakit pinggang lepas cirit birit memang boleh happen sebab dehidrasi dan perut kena kerja keras, tapi sebab you're 6 months pregnant, better check with your doctor just to be safe, ada few of my mum friends yang thought it was normal gastric tapi turned out something else kena monitor during pregnancy. Make sure you drink plenty of water and rest, but jangan delay the check-up tau!