HAVING TROUBLE

Hi all well I had my first kid at the age of 17 go on 18 and I breastfeed her until she was a month old because I got mastitis in both of my breast so I stoped and when i did my periods haven't been regular they come and go wherever it wants to but now she is 2 years old and I have been trying to have another kid for the past two months but nothing is happening and I'm having sex two days before I'm ovulating and when I'm ovulating. So does anyone know anything that can help get pregnant please.