Regarding pregnancy of my girlfriend.

Dear sir/ma'am, Me and my girlfriend had unprotected sex on 1st week of Dec, then she took I pill about 22 hours of sex to be safe from unwanted pregnancy but she got vomiting after 8 hours of taking I pill. But she got periods on 23rd of Dec for a day and half which too about a week earlier then her normal date. And again in Jan she got period for a day around 15th and this month in Feb around same 15th Feb she got period for a single day only. So we are worried that is she pregnant? She has put on the weight little bit and we can see his tummy bit more then normal. Is there are any chances of pregnancy despite of periods coming (it comes only for a day since last 3 months) and taking I pill? And if pregnancy chances are there then what should we do now ?