I'm on day 3 of ewcm but OPKs are getting lighter?

I usually have 2-3 days of good cm before I ovulate and then a day after, but I still haven't got anywhere near a positive opk. Is it possible I ovulated earlier than I got any ewcm? It was a little sticky 4 days ago and I didn't test until 3 days ago. I'm doing 3-4 hour holds each time I test.