what's the difference?

I'm studying English tenses, and right now, in particular, I'm studying the past. 
Today I've read about Past perfect and Past perfect continuous, and I don't understand the difference between these two tenses. 
I perfectly know how to form these verbs perfectly, but I need a clarification about the use of them. So, when do you use the first and when the second? 
This doubt has come came into my mind this afternoon when/while I was thinking at about this situation: 
I woke up and I looked out of the window. I noted/noticed that the sun was shining, but the ground was totally wet. It had been raining all night. 
now immagine the same little description but instead change the last sentence to: 

it had rained all night. 
I don't understand the difference, 
please help me =) 
Fab

Hello Fab! First of all let me tell you that your English is fantastic! Secondly, "it had rained all night" vs "it had been raining all night" can be used interchangeably. There is no real difference at least in this context. Perhaps you can see it more in this example: 

He finally showed up at the train station around 5 in the morning. I was exhausted, I had been waiting all night. 

vs. 

He finally showed up at the train station around 5 in the morning, I was exhausted, I had waited all night. 

These two sentences essentially mean the same thing. The first one however brings up more of an empathetic response. It expresses with more detail what that person went through to the person they're speaking to. But really, they mean the same thing. I wouldn't worry too much about it :)