Also, there is a myth that you cannot get pregnant if you have sex when you are menstruating. This is not true. Always assume that you will get pregnant if you have sex without using birth control. There are many little clues that you are ovulating, but none of them are very reliable. You start to recognize your own personal clues by paying attention to your cycle.
Some women feel tiny twinges on one side of their belly or the other.
Your sense of smell and sight may be more sharp than usual. Your vagina gives off slick, stretchy discharge when you are most fertitle. Another way to tell is to take your body temperature every morning before you get out of bed, and keep a record of it. It rises a little around ovulation and stays high until your period begins. This is a method that women who are trying to get pregnant use to figure out when they are most fertile.