Does the depo shot really stop your periods..?

I'm looking for another method of birth control that doesn't require a good memory. I'm on the pill now and I have to set an alarm on my phone to be sure I remember to take it. It's annoying. I thought about getting the depo shot but after my mom told me it didn't stop her periods (gave her 6 months of straight bleeding instead) I forgot about that one. My doctor told me I could get an IUD like Mirena but that those cause intense pain during insertion and for days after so I don't want that either. I just want to know how likely it is that the depo will really stop my period like it's supposed to or actually make me bleed for months on end. My doctor couldn't give me a real answer and just said that it can go either way and as I'm not too keen on just waiting to see what will happen, this kind of answer just doesn't really help.