It could be chemical pregnancy. My SIL has the same encounter, try reading more about it. She tested twice at home & it was positive. Went to polyclinic & it was also positive. Went to KKH O&G, nothing found via scan. Doc said it was likely chemical pregnancy, her bf left her the very same day.
wouldn't want to scare you but it might be etopic pregnancy cause I've been through the same, doc is not able to see my baby at 11 weeks n I was spotting.. but please do have another scan n check up with your gynae. I hope n pray the best for you.