No, it is highly unlikely that thrush can affect your ovulation. I couldn't say that it is impossible. If you have been unwell other than that, that could have affected your cycle. Ewcm is nothing like leftovers! It looks and feels very different. I would recommend that you use another method of tracking your cycle. Ovulation testing worked great for me. No matter how long my cycle is, I always get the period exactly 14 days after the surge. So I always know if it is late. For most women, the second half of their cycle is reliably constant, it is the first half that changes length. I just used the cheapies off the internet, but in the past I tried a fertility monitor too which was helpful.