Ah sama la, 26 weeks dah rasa heavy kan! Sakit pinggang dan kaki bengkak tu very normal sebab baby dah besar and hormones make your ligaments relax lah. Few of my mum friends cakap stretching, pelvic exercises, and paracetamol when kena really bad helps, or try support stockings, ada jual kat pharmacies. But since you're already at 26 weeks with pain, better mention to your doc at next checkup so they can rule out anything else, especially since pregnancy can bring different issues. Yang penting make sure rest enough, angkat kaki when you can, and drink lots of water!