Thanks for the query.
Scanty flow during periods is called hypomenorrhea
and that can occur due to many causes.
We cannot confirm the pregnancy
just by symptoms. But if pregnancy is there according to your description there is possibility for ectopic pregnancy.
Though this is a rare condition better to rule out as it can create emergency condition.
So you better consult gynecologist and undergo physical examination and ultrasound
to rule out this possibility.