Period and light spotting

Hi there.

I took a pregnancy test 4 days ago it was digital result said no. I am 3 days late and last night I have a very light spotting when I went to bathroom I mean very light couldn’t hardly see it. Thought I was starting put tampon in just in case woke up this morning was very very little and light colored like spotting. Now nothing. But the last few days I have been extremely light headed, nauseous, heartburn and super tired which I thought was due to my medication I’m on for tooth ache that is getting taken care of Thursday morning. I’m beginning to think I’m pregnant but no other obvious signs that I can tell so far.