Break through bleeding?

Hey ladies I have a question? I know it is probably a dumb one but ugh it keeps nagging me. Okay this cycle I was five days late for my cycle. I'm usually very regular. Then on the fifth day I spotted very light. On the fourth day it go a little heavier but lightened up again. I googled about it and found some articles on breakthrough bleeding. I was wondering how many of you experienced this, did you show positive on a hpt, and what was your other symptoms that led you to test? I want to test myself but I'm afraid that I am working myself up for nothing. Its just my body feel so differently this cycle. Any and all comments will be very appreciated.