Hello and welcome to EmpowHer,
There are many factors that could be effecting your ability to get pregnant. Factors can include:
--not having a regular period means you are probably not ovulating every month
--the fertility of your male partner is a huge factor
--any drugs or medication including birth control
--condition of the ovaries and uterus in general
If you really want to get pregnant you will need to see a gynecologist.
Below I have pasted a link to a HER article that talks about treatment for infertility.
I hope that helps.