Opinions please, TMI!

I posted this as well in a different group, but here again!

So, my last period ended on Nov 29th. On Dec. 9th I had protected sex with my BF, but while switching positions I accidentally pulled the condom off of him. We immediately stopped and did not continue, nor did the condom break. Now, my regular cycle ranges from 30-35 days so this would now be the longest considering I was supposed to have my period Dec. 27th. However, I heard that stress can cause delays and this month has been STRESSFUL. I had finals, fear of lowering my GPA, a loved one having extreme surgery, insomnia, not being able to work for around a month, and of course the holidays. I did buy 2 pregnancy tests but am too nervous to take them since I heard a lot of negative feedback from the brand. The one I picked up was the Clearblue digital strip that uses words instead of lines. I am only 20 so I am definitely not wanting a child as of now. I know it is all probably in my head since I am still having a few normal pms symptoms, but I want to hear opinions! Not only on the situation, but the pregnancy test too! Thanks for reading the long post.