Aw mama, ligtas lang yan at super common sa ganitong stage! A few of my mum friends said the same thing around week 36, ang berat ng baby pulling down talaga, and your body's preparing para sa labor so everything's loosening up. Try pelvic support belt (sobrang tulong), frequent rest with pillow under your belly, warm compress, at mga gentle stretches, pero honestly best na i-mention mo sa OB mo next checkup para ma-rule out anything else at para may proper advice ka for your specific situation. You're almost there na, mama!