Ovulation test

Janine

Hello ladies quick question I done a ovulation test this morning and it came back positive I’ve now done another one after work at 2 pm and it is a negative I also done one last night about 4pm and it was negative as well as the day before so surely I couldn’t have ovulated already from my positive.., my cycles are 30 to 34 days and I am in my 18th day from my first day of my period