Really confused and feed up...

Okay once again I'm having brown spotting when I wipe. AF due "suppose" to be 17/18. Normally I have 32/33 day cycle. Well today is day 30. It did this last month also. I'm so confused. I did opks on day 16 like it said to, and I goy the surge on friday which was day 18. So suppose to ovulate within 12-36 hrs but its not a fure sure thing. Okay so I bd wed night and sat night. Took a test this morning neg it was. Then I wiped and I seen the brown discharge/spotting. So does this mean my cycle moved from 32/33 day to 30/31 day now? Ugh.. I'm feed up with my body...