Most irregular period ever...

About two weeks ago now I had spotting g for one day, after that I didn't notice anything for a week. Then a week later I started a "period". It's mostly just been light pink and brown spotting/light flow with a few hard quarter sized clots. I thought it was over after about 4 days (much shorter than my usual periods) and had stopped bleeding for 24 hrs. THEN, I notice some more light bleeding. This is VERY unusual for me. Is this common or should it be a cause for concern? Any ideas/tips/stories welcome! Thanks ladies!!