i am having the same problem. i'm on my 2nd pack of Cerazeete and the first period while on this pill lasted for about 3 and a half weeks. i stopped bleeding last monday and now im on my perid again which started on monday. i went to see my GP last week and he told me finish the 3 months pack and if the period doesnt get stop or get better come back. this is really frustrating as these pills were prescribed to be because i was having heavy/painful/long periods but with these pills its the worst period i've ever had. i will go back to see my gp after i've finshed my 3rd pack and hopefully they'll be able to give me something else