36 weeks back pain

Hi everybody.

For the last week I have had severe lower back pain on my left side that causes me to limp really bad when I walk. It hurts to get up, roll over, bend at all, and put weight on my left foot. I typically am a very active person and am finding this pain pretty debilitating. I was going on normal hikes just 2-3 weeks ago but now I can hardly stand to walk to the bathroom from my couch. My left leg also seems a little weak, it’s buckled twice under my weight this week. Does anyone have experience with this? What helps and is it normal to have this level of back pain at 36 weeks? I feel like whenever I mention pain to my OB she just says it’s a normal part of pregnancy. But I also get anxious talking to doctors about my symptoms so I’m sure I underplay my discomfort at the OB office. TIA!