Ay, mahirap sabihin based on pic lang talaga, pero ang light brown-reddish spotting 3-4 days after your period ended ay pwedeng maraming reasons, sometimes it's just leftover bleeding from your cycle, or it could be implantation bleeding if may nangyari kayo sa fertile window mo. Honestly, sis, the best way to know is to take a pregnancy test after a few days or check with your OB kasi they can tell you exactly what's happening and confirm kung buntis ka na or hindi, yung timing mo ay plausible for pregnancy pero kailangan ng proper check talaga to be sure! A few of my mum friends found out through blood tests at the clinic rather than home tests kaya mas reliable, lalo na kung first time mo. Fingers crossed para sa'yo!