My period is always regular. But this month it came 3 days early, was light, and only lasted 2 days. I took a pregnancy test today (suppose to have started my period today) and it said negative. I dont know if maybe I took it too early?
If you are suspicious you may do a test in about weeks or ten days time. Once i also got that and when I asked my doctor he said it can't be implantation bleeding and it has happend due to hormonal imbalance.