Well first off, you shouldn't have followed your friends advice...you should have gone to a doctor. Taking birth control pills is not going to help you get pregnant.
I have had irregular periods all my life. In high school my doctor put me on birth control pills to regulate me. That worked for awhile then stopped as well.
Bottomline, I don't have any periods unless I am on some type of medication.
You really should go to your doctor. Tell them you are trying to get pregnant. They will do a pre-pregnancy check up and will include blood work to make sure all your hormones are at the right levels to achieve pregnancy. If you have been trying for about a year, they will probably send your husband to get tested too.
I have a 5 year old from a previous relationship, my husband and I have been trying to concieve for a little over a year now without any luck. We both have been tested and are fine...although they still are not sure why I don't have periods.
My OBGYN put me on a medication called Prometrium. I take it 10 days out of every month. This medication forces me to have a period, thus regulates me so I can pinpoint when I ovulate.
If you are not having regular periods you are going to have a hard time figuring out when you ovulate....and that is the key ingredient to getting pregnant. Once you regulate you periods it may be easier for you to find your window of fertility and thus get pregnant.
You really need to see a doctor....I was SO scared they were going to tell me for some reason I couldn't have kids...but really, me and my husband just need a little help
Good luck!