TTC and breast feeding

My son will be 1 on April 1st and I have been tycoon since November. I know that if I'm still breast feeding it makes it nearly impossible to concieve. I have tried to do ovulation test kits and it says when I'm suppose to but I don't think I am. :( I am going to be weaning my son off the breast. It has been my plan since he was born to breast feed him till he is one. I'm not just stopping cause I want # 2. Does anyone know if I will start to ovulate immediatly after I wean or will it take like a month or two?