Mama, I know it's scary kaya please don't wait, call your OB tonight or go to the nearest hospital if the pain gets worse or you notice spotting, unusual discharge, or if you feel dizzy, okay? At 37 weeks, any sudden pain needs checking ASAP, hindi lang bukas.
A few of us moms experienced ligament stretching and pressure pain towards the end, pero with that lower belly heaviness too, mas safe na makausap ang doctor agad. She'll know exactly what's happening with baby and make sure kayo both okay. Sending love, you're so close na!