Welcome to Healthcare magic
To begin with, try to relax and not take things too far.
One can not be pregnant with out having sex or a medical procedure intended for getting one pregnant.
As far as I can guess from the history that you have come up with, you neither have had sex nor did you opt for a medical procedure aimed at getting you pregnant. So no you can not be pregnant.
Pelvic scanning/ pelvic ultrasound
is not necessarily a test for pregnant women. There are lot of possible diagnosis where this scan can be helpful e.g fibroids, ovarian cysts & other tumours of the uterus
or the ovaries.
So if the bleeding was normal this time around, it does not necessarily mean that the issue has resolved. At present it would be best to get the ultrasound done to rule out any diagnosis that may require an urgent course of action for treatment.
Hope This Helped you understand
Please do let me know if you require further clarification