Ay sis, normal talaga yan sa pregnancy, especially around this stage! At 28 weeks ang uterus mo ay sobrang laki na and it's putting pressure sa bladder mo, kaya feeling mo palaging puno even after you just went, a few of us pregnant moms complained about the same thing. The good news is it usually gets better after delivery, but if you're noticing anything unusual like pain or burning when you pee, better check with your doctor para sure lang na walang UTI or anything, kasi yan din common sa pregnancy.