irregular cycles

Does anybody have irregular cycles? I came off the pill in January and I'm still not pregnant, I thought it would happen very quickly as our first child was a lovely surprise when I was on the pill. 
Anyway after logging my periods on this it seems as if my cycles can range from 19-24 days! So I never know when I'm ovulating, I've been trying to go off CM but it's not helping, can anyone recommend anything? 
I'm currently taking folic acid but that's it.Â