Can I have miscarried and still get a positive test

[Olofsdotter]

Hi,
I might be 6+5 weeks pregnant if you calculate from my last period, but here is the complication; I think I got pregnant the 11th of Nov as we did the deed and I ovulated, ( maybe could’ve happened on the 17th too but I didn’t have any ovulation signs then so I think that would be too late) but I got my period on the 20-25th of Nov like normal and it was quite heavy. Everything I’ve read suggests an implantation bleed is very light.. I did a pregnancy test on the 6/12 on routine as we’ve been trying since the summer, and it was positive. ( clearblue suggested 2-3, I.e. 4-5 weeks) I can’t have got pregnant after the 18/11 as I was away until the 5/12.
Can I have miscarried when I thought I had my period and the test is just showing positive because the hcg is still high?! I’m freaking out now thinking about that!!!
I don’t have any typical pregnancy symptoms, perhaps my boobs are a little bigger and more sensitive but it could be normal hormones I guess.
I know I can’t get anything confirmed until I get a scan but it would make me feel calmer if anyone has had what they thought was a normal period but then they were pregnant anyway.