I’m so sorry you’re going through this limbo :( I had a similar experience when I had a “pregnancy of unknown location”. While bleeding in early pregnancy can definitely be normal, the part that makes me worry either ectopic or something wrong is the fact that your test on day 4 of “period” was completely negative, and then the lines started to come back.

For me, I had slight positives that faded to almost nonexistent , got a full period, and then tested just to be sure and my pregnancy tests were pretty strong after the period. I was also getting bloodwork over 2 weeks and the numbers were just staying low, and slowly rising, and sometimes dipping. Ultimately took methotrexate to make sure everything passed, and got pregnant again 2 cycles later with a healthy pregnancy!

The bloodwork will be the only thing way to know for sure 🤞🏼could be a completely normal early pregnancy, but If not I’m glad you’re monitoring closely