Ovulation pattern

First clomid cycle 100mg, I ovulated CD13- confirmed with BBT chart, CM and my period came at CD28. Now, second cycle of clomid 100mg, I'm CD 17 and no ovulation sign noticed. No temperature jump, creamy CM and really sorebreast. It doesnt look like I will ovulate this cycke.... Is it possible that clomid make you ovulate but not every time? Have you ever experienced something like that?