Do you believe in ghosts?

It's just that I have always believed in ghosts and when my mum got cancer 2 years ago when I was 12 she always said that when she died she would sways do everything she couldn't to just make a sign that she is ok. Even if it was getting a rub on my hair, a tap on the shoulder. But nothing and she's been gone a year today. I've always believed in ghosts because of the overwhelming Evendence for them and no proper evidence for god. But know I'm not sure if I do because I know because she hasn't left be a sign it means she hasn't been able to get to me.