Doxycycline and Plan B

I started taking Yaz but stopped after the first week of pills because I lost the pack. Shortly after on the 7th I spotted or had my period ( its hard to tell because my periods are very light and no more than two days long). On the 25th I had unplanned and unprotected sex. Two hours later I took Plan B. I am also on Doxycycline ( 20 mg per day). I heard that this antibiotic can reduce the effectiveness of the emergency contraceptive. I also heard that drinking alcohol will metabolize the Doxycycline faster from your system. I'm supposed to get my period on the 28th but I dont know if i will because i had spotting on the 7th.
I've stopped the Doxycycline just in case I am pregnant but I have no idea what to expect. When will I get my period? Did the Doxycycline ruin my chances of preventing the pregnancy? Did the abundance of alcohol I had that night eliminate the Doxy from my system?

[des84]

antibiotics do decrease the effectiveness of the plan b and also of birth control pills. you might not get your period on time because the spotting. and the alcohol probably did a number to the doxy if it didnt wipe it out. i would wait till the 7th to see if you get your period and if not take a test. if its negative then start a new pack