Oh anak, I'm so sorry you're going through this again, alam ko kung gaano kayo kabilib after everything you've been through.
Please go back to your OB na right away, o pumunta sa emergency room kung kailangan mo ng same-day check. Light bleeding + fading test lines + no sac on ultrasound yet could mean a few things, but your doctor needs to see you in person and maybe do repeat scans or blood work, Hindi kami makakasagot nito here, at deserve mo ng proper care ngayon.
A few of us moms na may history of losses did blood work to check hormone levels, that helped their doctors figure out what was happening. Your case with your tube situation is really specific, kaya kailangan mo talaga ng medical team na nag-monitor sa inyo closely, not guessing online.
Stay strong, mommy. Text or call your OB today, okay? You're not alone.