Hi there Chow
Generally speaking Raven is right in what she is saying by counting back 14 days from the beginning of your last period to determine around when you would ovulate. Also some ppl don't even notice the CM (cervical mucus), there is a product called pre seed that some ppl on here swear by, so maybe if you are a little drier so speak you could try that, go to www.lullabyconceptions.com.au Although you don't think you are that regular,you are considering what i was like, mine went from early 30 right up to 50 something from one month to the other but i just perservered.

Best of luck, i hope this is your month also!