Sayang, please see your doctor or go to the hospital today, a few things you mentioned together (the hardening, the diarrhoea for a few days, the pain when you move) really need a check-up to be safe, especially at 28 weeks. Don't wait lah. Your mum friends and I always say if something feels off and it's been going on, better to get it checked than worry at home, the doctors won't mind, that's what they're there for. Call your clinic now or head to the nearest hospital maternity unit, okay? Take care of yourself and baby.