I had an unprotected sex with my girlfriend on12 dec,2012 (next day from her end period).I didn't ejaculated inside her vagina though she took i-pill within 7hrs. After one week she got some blood.Then she took a test with preganews kit and it was negative. After that on dec25  we had sex again using condom. on jan 2013 she have got her period normally(but it was lasting for 8days). After that we had sex on 6th jan using condom.Now she felt fatigue and some hard substance in her lower abdomen portion. Is there any chances of prenancy or something else?pls reply soon and give proper suggestions(medicine) to avoid it...