Need help please

Hello, I started on propecia in 2015 which I shedded loads, then 15/10/2016 it stopped, my head ich went and my shedding stopped, I was soooo happy, but until know iv started shedding hairs and my head ich is not constant as before but it comes on in periods. Has anyone had a experience like this before? It worked for like 10 months then just stopped. If anyone has any idea why this has happened and will it pass? Sorry for bad grammar and spelling my English is poor.