Question tmi no pic

Saturday I had an almost positive opk since then they have been getting fainter so I think Saturday's when I o'd. Yesterday I had a huge blob of yellow tinged Ewcm that stretched like 3 inches. Never had anything like it. What is it? Is it fertile or no? I am on cd 20 right now. And usually have 35 day cycles. First month taking vitex. Any answers appreciated.