 [ Symptoms ] can levonorgestrel i pillplan b cause periods to be one week early my periods started on 29th jan 15 ended on 3rd feb 15 on 4th morning around 7 30 am was fooling with my bf when he inserted in me max for 5 mins he pulled out but i was scared of precum he never ejaculated inside on 5th feb i took levonorgestrel i pill  plan b 38hrs later my next period was due on 21 feb as i have 24 days cycle but my periods started today 13th feb one week early so are there any chances of pregnancy [ Disease ] sometimes coming off a medication especially a psychoactive like an antidepressant can cause odd side effects like that it has to do with the brain readjusting to not having the medication but it is not usually harmful you might want to mention this to your doctor if it become really bothersome