shorter period than usual.

Hey y'all! So on 1/24, I tested negative on first response that morning. I had woken up that day with a horrrible headache. I threw up a couple times, and just felt sooo crampy. Well my period ended up starting. What has me in question, is the fact that today is cycle day 3 and I haven't bled in 24 hours. So legitimately, cycle day 1, (1/24) was horrible cramps wise, but my period was still light. I never soaked a pad or tampon at all. Just light spotting. Then yesterday light pink spotting. And  mid day to today, has been nothing. Has this happened to anyone?? Am I just irregular? Could it be pregnancy? I'm just confused. I always usually bleed at least 4-5 days with the first 2-3 days being at least heavy enough to change out every 4 hours.