im 30 years old and have a 17 year old son that i had at 12, for the past 15 years ive been trying…

im 30 years old and have a 17 year old son that i had at 12, for the past 15 years ive been trying to concieve my second child and it still hasnt been successful, ive been to my gp several times at different doctors surgerys and they have all told me that there is nothing wrong and everything is normal without doing any tests, its like the doctors assume i can have another child because ive already got one, i just wanna know if anybody knows what is going wrong my body for me to not concieve ive also got a green liquid coming out of my breasts after having my son 17 years ago