Thanks for your query.
It does not necessarily mean a pregnancy, but altered menstrual bleeding CAN indicate pregnancy or any of its related complications.
Possibilities include an ongoing intra uterine pregnancy, an ectopic pregnancy or a miscarriage
Also, anxiety, stress, thyroid hormone imbalance
, polycystic ovaries
, endometrial hyperplasia
also should be ruled out as potential causes by consulting a gynecologist.