Help! Very low HCG at 4 weeks? Any experience of this?

[JaS2021]

So I’m 4+4 and was admitted to hospital last night with suspected ectopic due to feeling very dizzy, clammy and one sided pain. They took bloods and my HCG was only 48. They then gave me a pelvic exam and said my cervix looked like a miscarriage had started and to let nature take its course. They reassured me that at this stage nothing would be seen on a scan anyway. I have to go back tomorrow for a repeat HCG.
I came home and just felt devastated and went to bed expecting to wake up in full blown miscarriage. But no pain, no blood, still feel pregnant. My partner thinks I shouldn’t be so hopeful and to trust the doctors but I just don’t feel like I’m miscarrying at all.
I had my positive test on the 18th but it was quite faint. I’ve done multiple tests since and none have been strong positives but I’ve had lots of sickness and sore boobs. Surely I could have implanted really late, perhaps as late as the 16th which would mean I’ve only actually been pregnant for about 9 days so surely my hcg could just be taking a little longer to double? Am I just clutching at straws here? Anyone else had really low hcg but gone on to have a normal pregnancy? Obviously I just need to wait for my next bloods but I’m driving myself loopy here!!!