Lower back pain

I’m 25 weeks pregnant and yesterday I started experiencing some lower back pain. I work at a restaurant and I have been working 8 hours shifts and I’m constantly standing so at the end of the day my legs kill me!!! But yesterday I got that back pain and today i still have it. It only hurts when I’m standing or walking. So I’m trying not to stress myself and think it’s just because I’ve been working a lot. Has anyone had this happened to them ?