Hi Are your periods regular? If yes, then you need to calculate your fertile period. If you get your period every 28 days then your fertile period would approximately be between the tenth and eighteenth day of your cycle. So intercourse in the fertile period will increase your chances of getting pregnant. If your cycle is longer or shorter you will need to add or subtract days accordingly to find your fertile period. There are many online sites available to help you find your fertile period easily so do a Google search on that. If your periods are not regular then you will need to see a doctor to regularize your period as having regular periods is important to get pregnant and maintain pregnancy. Using emergency contraception should not necessarily decrease your chances of getting pregnant. You have not mentioned your age or if you have any health issues. It would be worthwhile to consult a gynaecologist to do a complete check up to know if you have any conditions hindering your chances of pregnancy. Alcohol consumption does reduce fertility in the long run. If you feel your partner has an alcohol problem , you can consult your doctor who can help him get a semen analysis and help him with his Alcohol consumption. While you re trying to get pregnant it would be wise to start prenatal vitamins containing folic acid. Also try destressing yourself, many times it helps to not be so obsessed about it, as you yourself have mentioned that you got pregnant when you least wanted to be. I hope this was helpful. I wish you good luck :)