Back pain at 5 weeks

Ill be 5 weeks on Sunday! I’ve been experiencing some incredible lower back pain the last 3 days that doesn’t start until the day goes on after I’ve been on my feet. I’m a waitress and it tends to start about an hour or so into my shift and progresses throughout the night. I’ve been getting so uncomfortable that I feel like I can’t stand anymore when I get to that point. I’ve been taking 1 tylonel after work & using a heating pad and it tends to lighten up. The pain is mostly pretty low but sometimes radiates into my tailbone and pelvic area. I called my nurse & she said that it’s rare to be having back pain this early and that as long as I have no abdominal pain I’m fine. My anxiety has been so bad I’m so worried about miscarrying. Has anyone else experienced this?