Is Light Red Spotting For One Day Sign Of Pregnancy?

hi my name is jessica im only 20 year old i need help on aug7 i want to nj to spend 3 weeks with my bf we had sex on the same day on aug16 i had my perido it was over on aug20 we had sex undtill the 31th of aug we had sex befor i want home on sep9 i want to the bathroom and i was spotted light red blood and it stop the same day to the 9th to the 18th of sep i still diding get my perido can i be pregnant i need help