Ay, normal yan sa 28 weeks, mama! Yung tigas ng tiyan mo ay likely Braxton Hicks contractions, practice contractions lang talaga, hindi ang actual labor contractions. Pero yung heaviness na feeling mo at yung parang naiiri, importante na i-check mo with your OB para sure na lahat okay lang, lalo na kung sobrang uncomfortable or may spotting pa, kaya best to reach out sa doctor mo para peace of mind mo.