Well, I just did my OPK, and it's still negative. The line is almost identical in darkness to the one I did 24 hours ago, so either my surge happened during the night or it hasn't happened yet. The third option (which I'm hoping isn't the case) would be that my body geared up to O but didn't succeed. I guess I'll wait and see what my temperature is tomorrow. I wish I wasn't feeling so impatient.