you could try identifying when you ovulate, which can be done by taking your temperature (try http://www.ovulation-calculator.com/basal-body-temperature.htm, and there are many more websites if you google it). you can also search for ‘rhythm method’ (http://en.wikipedia.org/wiki/Rhythm_Method), which uses the same knowledge for opposite ends. i don’t know anything about tilted uterus, but see that there are articles online. have you seen a gynecologist?