The ovulation test doesn't tell you when you ovulate. It just tells you when you have your LH surge. It is quite common to get two or three days worth of positives. When you get a positive opk you typically ovulate one or two days after but it could be as late as 3 days after. Are you sure the first positive was a positive? Was the test line at least as dark as the control line? If so I would consider that most likely the start of your surge.
Here is one of my charts where I had three positive opks.
You only ovulate on one day out of the month. You wouldn't have ovulated for three days but it is hard to say for sure what day you ovulated on if you weren't charting. I would give yourself a three day window starting from the day of the first opk.
Also, were you paying attention to your cervical mucous? The last day that you noticed slippery cm would be your most likely o date. You normally dry up shortly after you ovulate.