Delayed Preiod Pregnancy Chances

[h=1]Hi, I am Smita,24. I usually have a 28-day cycle working perfectly. Me and my husband had sex on 13,14,15 October. There was no ejaculation inside the vagina. He pulled out the first time much before, and later we used condoms and for the fourth time we had without condom again, but this time he didn't ejaculate at all.(even outside). The problem is that I had my last period on 1st October and am expecting this 29th. But I am yet to have my periods. We have tested using home pregnancy kits on 1st november and again today(4th nov). It was negative both the times. My concerns: 1. Having read on many forums that home kits show false negatives. 2. I am having sore nipples, which was never the case before( and I found that its a pregnancy symptom) 3. many online forums posting the pregnancy symptoms--all seem relevant 4. i have my exams due december. Please tell some sure way of confirming pregnancy or if there is a chance for pregnancy at all? What should I do?[/h]