What is going on?

My husband and I have been trying to conceive, I have had suspicions that I may be pregnant from symptoms, such as nausea, tender breasts, etc... I went to my ob/gyn for an unrelated matter yesterday, and ended up taking a pregnancy test there. It was negative. I came home and took a FRER I had laying around. It was the faintest line, but there. I called the doctors office back, and they sent me for blood work. This morning I woke up and took 4 more FRER and 2 Clearblue’s. All had faint positive lines. I then got a call from the doctors office that my beta-HCG test came back as 0 and I’m not pregnant. I swear my tests at home were positive. What could be happening?

UPDATE: Took another FRER this morning, I still see a faint line. Going back to the doctors this afternoon to see if they can make sense of this. I’m hoping there was human error at the lab, but we will see.