Menstruation while breastfeeding
Every woman is different, but many will notice that their cycle doesn't come back until after they wean their baby. I have two children, and had no periods while I breastfed. My oldest child was weaned at 18 months, and my younger a little after his second birthday. Not having periods all that time was a wonderful side effect of breastfeeding! Some ladies do get their cycles back while they are still nursing. In most cases, it will happen after you introduce solid foods to your baby (and there is less nursing). You may have a few anovulatory cycles, or could start ovulating right away.
Cycles after breastfeeding
Once I stopped breastfeeding, my cycle also came back. In my case, it was extremely regular immediately. For some women, it takes a while for periods to become regular again. Both variations are normal, so you don't have to worry. If your menstruation doesn't start up for a while after you wean, that is normal too. If you have started menstruating and are wondering whether you are fertile again, doing ovulation tests is the best method of finding out for sure.
Many women have less heavy periods after they have given birth. If you were suffering from heavy and painful periods, your pregnancy and birth may mean that you will no longer have to deal with that. Remember that it is possible to get pregnant while breastfeeding as well, but not for everyone. Again, ovulation tests will help you determine whether you are fertile.