Really confused!!

Ok I thought that I had a positive opk on the 15th and 16th. I though it was odd because the last two months my nipples got sore around ovulation and I had ewcm and this month I didn't. Yesterday I noticed my nipples were sensitive and today had a little ewcm. So when I got home I took a opk and sure enough it was positive!! Darker than I have seen before. I got off of bc pills at the end of October and the last two cycles have been 28 days. I am on cycle day 22. Have I missed my chance for this month?! I'm so disappointed!! :(