I would definitely try to push for bloods to rule out ectopic, with mine my lines fluctuated from mega dark bfp to light then dark again, pain in my left side, which got worse over time, bleeding but not all the time, I didn't get any shoulder pain until my tube ruptured, luckily enough for me i was already at hospital waiting for a theatre slot so I just jumped the queue thankfully. Bare in mind I had several ultrasounds over a course of 3 weeks and they couldn't say where the pregnancy was, originally a pregnancy in unknown location, it's really not worth the risk, I would push for bloods x