Is My Girlfriend Pregnant?

My Girlfriend was on the contraceptive pill until around about the 15th of december until she suffered a migrane and was told to come of it. We have had unprotective sex since then but I have not ejaculated inside her. Its now the 20th january and we are both worried she is pregnant, her period should be due soon. We are confused as when it is due as she has just come off the pill.She does'nt seem to be suffering from any of the symptoms e.g sickness, spotting, tiredness. We are also worried if she is, what can be done, we are both for abortion as we cannot bring up a child, whats the best way to abort the baby?