I stopped contraceptive pills about 3 mos. ago due to Warfarin medication. Now I am delayed almost two weeks.?

I was diagnosed with Pulmonary embolism last October 5 due to DVT which the doctor said cud hev been caused by taking contraceptive pills for 3 years. I stopped the pill on October 5 and I'm on 5mg warfarin now. I had mens last october, november and december. My mens due shud be Jan. 4. I am delayed for almost two weeks now and I'm freaking out.I am scared of the effects of warfarin just in case i get pregnant. I am also on antibiotics for treatment in my gum abscess. I took Pregnancy Test last January 8 and it came out negative. I had unprotected sex last December 24. Please help. I have been stressed too much because of this. Is there a possibility that I am pregnant and that my medication is affecting my pregnancy test result? Thank you in advance.