Ay mama, normal yan lalo na sa 35 weeks, ang bigat ng baby at umuusog na siya kaya sobrang stress sa likod mo! But since it's been 2 days na at nag-worry ka, better check with your OB just to be sure it's not anything else, okay lang naman gawin yan for peace of mind especially first time mo pa. In the meantime, try warm compress, good posture (easier said than done, alam ko haha), at baka kailangan mo na rin ng maternity pillow between your knees when you sleep, totoo talaga yan, game changer.