Need some advice.

So on the 18th of June. I had my first positive pregnancy test. By the 20th I started some light bleeding by the 22nd we had done 2 more tests that said positive. On the 23rd we went to the early pregnancy unit and had a scan, they couldn’t see anything on the screen but I had bloods taken and my hcg levels were 34. I returned on the 26th for more bloods and they had dropped to 15 and we got told I had a missed pregnancy. 4 weeks past and still no cycle and my breasts have been killing me. So we done a test and it was a strong positive before 1 minute! We then done a digital 2 days later first wee of the day. And it said pregnant 3+ so when I work out the dates adding 2 weeks like it says on the leaflet. It goes back to the 19th June! Could my levels have dropped but still be pregnant? I’m confused to how far I am. I called the early pregnant unit and I have a scan booked in for next Thursday. I’m either going to be around 7 weeks if we conceived the same week we lost baby or 11 weeks if I didn’t miscarry at all!! 🤔