I got a question

My last period was December 17, 2018 my cycle are 35-37 days I been tracking since October 2018..... so my tracker told me my period was coming 24 and nothing I notice my period didn't come until the 27 of January. I started a spot on January 31 then stop I thought it was implantation bleeding once I look up what what's going on with my period and not to forget I had headaches backaches vomit fatigue , next day still spotting by the three day I think it was my period and got discouraged and sad. It's not Feb 3 and idk how to track my period the right way to know when my OUV will be to conceive has this happened to anyone