Welcome to the boards.
When taken correctly - which it sounds like you have been - the pill is very effective at preventing pregnancy. No method of birth control is 100% effective, though, so there is a small chance that the pill can fail. In typical use - how people usually take it, including sometimes missing pills - it's 91% effective: that means that over a whole year, out of 100 couples using the pill as their sole method, 91 won't become pregnant, and 9 will. In perfect use - always taking it exactly as it's supposed to be taken - it's 99.7% effective: less than 1 out of 100 couples will become pregnant.
Basically no-one will take medication perfectly for a whole year because we're human and make mistakes! So it's better to think about the numbers for typical use when you're making decisions about what you do and don't feel comfortable with per the amount of contraceptive protection you want.
If it's important to you that you don't become pregnant, we suggest using a second method as well for extra security, which makes the chance of pregnancy really tiny. If you'd like more information on how the pill works and what other methods you can pair it with, check out
Combined Oral Contraceptives (The Pill). Too, if you're having unprotected sex, you'll want to be thinking about STI risks and taking care of your reproductive health. Are you and your partner both up-to-date on your sexual healthcare, including STI testing? If you want to reduce your risk of STIs - which we'd recommend! -
Condoms are a major way of doing that, and they're also a great back-up method to add to your pill.
When you're using the pill, you don't have your usual fertility cycle, so the timing of sex won't make a difference to any pregnancy risk. When taken correctly, the pill is equally effective at any and all times of the month.