Can anyone who has had irregular cycles and got pregnant help me with this?

Hey ladies, I'm just wondering what are the early symptoms of pregnancy? I have lower back pain, I get heartburn, and mild cramps but my period isn't for another 3 weeks. I have irregular cycles so I am on birth control but had sex with my man during the end of my cycle. I know what you're thinking.. "Gross!" And I don't blame you but shit happens! Anyways, if you have also had irregular cycles or on birth control and still have a child.. Please tell me what the early pregnancy symptoms are. It will be two weeks since I've had sex while on my period next Thursday. Any advice whether the symptoms I listed are accurate or not will help me tons! Please and thank you! Just trying so hard for a baby.. We are looking to complete our lives with the most precious gift life can give. Also any advice on how to get pregnant will help. Thank you again and I hope to hear from you ladies!!