Any advice appreciated :(

My partner and I for giggles decided to take a pregnancy test turns out it was an instant positive but here's the kicker I've been bleeding for the past 11 days on and off bright red I had really bad ovary pain yesterday. I thought my PCOS was playing up and my cysts were bursting. worried I was having an ectopic pregnancy, Hospital. They confirmed with another urine pregnancy test and took me for an ultrasound.my ultrasound showed nothing in my uterus nothing on my ovaries or in my tubes. My beta hCG test came back at 400. My ovary pain has stopped but I'm still bleeding on and off I've got no cramps no pains no nothing just a steady on and off bleed. They think that it I may be only just pregnant and it's too soon to see on the ultrasound and that this may be implantation bleeding or that this is the tail end of a miscarriage. I'm really worried because it's been since the 18th but my hemoglobin and blood count is fine so it's counted as a light bleed. has anybody ever been through this and still being pregnant this is my fiances first baby and I don't want it to end in Loss. we've been trying for 14 months and we just want to complete our family. The doctor suggested waiting a week and doing another test to check my levels but it's eating me up inside. I can't help but think that if I was having a miscarriage I should be in pain. I previously had a missed miscarriage and I was in a lot of pain but nothing this time it's a lot of blood to think that the pregnancy is viable. I would greatly appreciate any advice or similar stories to help ease my mind or help prepare me thank you

please note top test is taken with a 1h hold and bottom test was taken with 0 minute hold approximately 2 minutes after first test was taken.