Positive urine hcg, but negative serum hcg?

I tested positive at home for the first time on Tuesday morning. It was faint, but definitely positive. I tested with a digital that evening and it indeed said pregnant. I asked my OB to order beta draws as I do have a history of pregnancy loss, and he agreed. I went in today for the blood draw. I have a portal so I can see my results before my doctor calls to tell me what they are. My beta was less than 3, which I know is negative. I was very upset and immediately went to the bathroom to take another digital test and it AGAIN said pregnant. My OB office is now closed and I am just so anxious. I’ve been reading on the internet (which I know you’re not supposed to do but I’m stupid and can’t help it) that when people have positive at home tests and then negative blood work, they normally are told that they probably had chemical pregnancies or miscarriages. If that was my case, wouldn’t I not have positive tests HOURS after my negative blood draw? Maybe I’m just holding onto hope that it was a mistake and I’m still pregnant, but I’m very quickly losing that hope and becoming very upset. Has anybody literally ever heard of this happening?

I don’t know if it helps, but I would be very early. Like just over 4 weeks pregnant, early.