I started when DS was 3 months old (consequently when he started sleeping all night too). And I nursed him until 14 months then after that it is once every few days he tries but gives up since I have no milk left.
Quoting Kayla Bliege:" my baby is almost 6 months old... she couldn't handle the milk so she is on special formula, I had my tubes tied but I still have pain from that and no cycle so that is why I am concerned"
Just depends on your body really. And with getting your tubes tied that probably effected your cycle in some way as well. If nothing else take a test and set your mind at ease that you aren't pregnant!