Lines getting fainter, pain but no bleeding?

[YassQueen]

I'm approximately 5 weeks pregnant. I've only had faint lines - I've been testing every two days, on different brands so not even a batch/brand problem - and today's test is fainter. I've had proper cramping period type pains on and off for almost a week, and a couple of days where the pain was in one side and my shoulder (I was worried about ectopic but the pain comes and goes so I don't think it's that).

I tried to get a GP appt today but couldn't get one, will they be able to do bloods and check the hormone levels? I'm fairly sure I'm miscarrying but in prev MCs I bled a lot shortly after the pains started. I don't understand why tests are still coming up positive but faint? Is the GP the best port of call?