Well, I can't know exactly when you're expected to ovulate, as I don't know how long your cycle is. You can always look up an ovulation calculator online, which can tell when you're expected to be fertile, so that you can be pregnant. Sadly, this isn't an accurate measure, as just like a period, ovulation days can vary from month to month. But it's just something you may be interested in seeing, though it's not something that can tell you whether or not you are pregnant, and can not accurately determine when you can have sex without getting pregnant (as you can never be sure when ovulation will actually occur) This being said, it's also important to remember that sperm can live inside the female body for 5, or even 7 days. So even having sex before your expected ovulation can still get you pregnant, since sperm can survive so long inside the body.
I can't give you a statistic that will tell you how likely you are to be pregnant. There's always a chance, especially since you didn't use any form of birth control. So is it possible? Yes, it is. How likely can vary from person to person, but given the time you had sex, you may have crossed over with the time you were fertile (just so you know, it's said that the safest time to have sex is two days before and two days into your period, but even this doesn't guarantee ~anything~).
As for determining the father of hte child. You would have to wait a bit, but then you could get a paternity test. It's basically something that compares DNA... if you are pregnant, you can go in and ask your doctor more about this procedure.
And as another note, for future reference... emercency contraceptive pills can be used up to 72 hours after intercourse. It is not meant to be used as a common form of contraception, but for cases such as being drunk and having unprotected sex, you can use the pill (the sooner the better).
Likewise, if you are going to be sexually active, and would like to continue doing so with different partners... I would suggest making sure to use a condom, to prevent STI (or STD) transfer. Just because someone looks healthy, doesn't mean that they are... STIs are commonly transfered because people don't realize that they have them. It never hurts to get checked, and then after that, play it safe to keep yourself health, and others healthy as well, don't you agree? And as before, if you want to keep having sex, you may also want to talk to a doctor about going on birth control pills, especially if you do not want to be getting pregnant. And if that's not right for you, you can always discuss other forms of birth control that might be better suited to you :).
Best of luck, and I hpoe things work out for you!