How Can i get pregnant?

Me and My bf have been trying to have a kid for over 4 months now... we have almost every day but when i have work. we try so hard and it fells everytime. i cant ever tell when im ovulation cycle cuz mmy periods are not regualer. i have birth control thats in my arm suppose to get out in june cuz it last for 3 years. but im also on the pill for periods. but the thing is i stop takin the pills so i can try to get pregnant and it aiint happening. im just confused.....