How many DPO am I?

My last period started on 12/14, but my ovulation sticks said I didn’t ovulate until 1/2. I had positive ovulation sticks on 1/2, 1/3, and 1/4. Since it happened for 3 days, how do I tell how many DPO I am? I have sore boobs and tingly ovaries/light cramping and feel like I am going crazy! I also had light spotting for less than an hour yesterday but nothing today. I took a test this afternoon and it was negative. Thanks for any insight!