My last shot was december 2011, i have had a regular cycle since 2011 i'm trying to conceive, but i haven't had any luck yet. what i need to do?

TTC: You don't say which of many shots you received. Was it a depo birth control? If so, it takes months to wear off, but it should be long gone after 4 years, and there is some other reason. If you have been timing sex with a regular partner at the right time during your cycle, and its been more than 6 months, you should talk with your doctor. Using an ovulation kit to predict ovulation may help.