Could Levonelle Be The Cause For Delayed Periods?

Hi, my last period commenced on 3rd october..i had sex with my partner on 9th and as a precaution approx 30 hours later i took levonelle one step! (there was alcohol taken on the 9th and wasnt sure if condom split although almost sure it didnt) i experiened some side effects..some abdominal pain..almost like the pre-period cramps..some spotting at various times..

My periods are regular and my next one should have started on 31st october, i understand that levonelle can mess up anyones cycle however im now quite concerned as no period has came (16 nov) i have carried out 3 home pregancy tests in the space of the last 2 weeks and all negative, can you please advise me on what to do and if theres any sort of medication available to bring on/induce a period. Many thanks.