Wondering if this happened to anyone else

Ok I know people are going to tell me to call a doctor and ask but just seeing if this has happened to someone else first. So, I am supposed to be ovulating this week and according to opk I'm not. I also had one day of one brown spot on my underwear. My period just ended a little over a week ago so I didn't think it was my period but put a liner just in case and it hasn't happened again. Does anyone know why I'm not ovulating and spotted one time? I haven't been on my normal routine either and haven't been eating healthy bc we were away on vacation.  Thanks for your help.