Help....

My period is pretty regular. Always comes on time and always lasts 5-6 days. AF arrived on July 19th which means it should have ended on the 23rd-24th. From what I could tell it was my period, it was a regular flow. On the 21st-22nd I stopped bleeding, I wasn't even spotting. On the 23rd I only spotted when I wiped and it was light pink. I assumed this was old blood or something. I didn't think that much in to this until my husband pointed out that I may be pregnant because I've been sick lately. I took a test a couple days after and it was negative. Could this be the cause of stress? Or am I reading waaayyyy too much into this?