Super confusing blood test result/pregnancy test result 🤷‍♀️

So ladies I got a faint positive pregnancy test on Sunday, went to get my blood drawn on Monday and my hcg came back at a 10. I started spotting on Tuesday but not much, then today went for a redraw and my hcg came back at a 12. But today I got a pregnant result on a clearblue digital. I believe those tests are 50 miu. So my ob called me and said this isnt seeming like a viable pregnancy. Can anyone shed some light on this? I'm SO confused