Confused

It was 31 days since my last period i took 3 ept test during the day all 3 came up with faint lines . I took another one the next morning just one line . My boobs been sore and my lower back also. I’m never late . Yesterday i went to the dr for for blood test i have not got my results back yet . When i got home i took a clear blue easy test it said not pregnant. Later that night i got my period 😥🤷🏽‍♀️. Has this happened to anyone else before .