Early period?

Has anyone for sure thought that they were pregnant but days later have a period that came early? My cycles are usally around 34 days and period came on day 27...it was normal bleeding like my usual period and lasted about 3 days with normal bleeding and the last two with light pink spotting....did I ovulate early or my cycles going to 27 days now? I've been on a pretty regular 34 day cycle for awhile..