Eh cramping macam period tu memang biasa during pregnancy, especially at 28 weeks, a few of my mum friends went through the same thing, tapi kalau sakit dia intense or followed by bleeding or discharge yang pelik, better la you check with your doctor just to be safe ya. Usually it's just Braxton Hicks or ligament stretching, especially cramping kat bawah perut, kaki, and back area. Drink lots of water, try to rest more, and monitor if it gets worse, don't ignore it kalau ada red flags. Kesian nak cramp macam tu, hopefully cepat improve!