I don`t understand the lyrics of that song,could you explain to me what refersplease?10 POINTS BEST ANSWER?

Is from the band The Easybeats(Australia)and is called Come in you`ll
get pneumonia
Here are the songs(there are two versions of the same group)
Lp version:http://www.youtube.com/watch?v=ykxXpHrklu4
Single version(here the lyrics are few
changed):http://www.youtube.com/watch?v=prFqcqHnqnk

And here are the lyrics:
My,my
look who`s at the door
standing in the rain
It`s you
and I thought you`d gone

All right,come in you`ll get pneumonia
you can stay until the morning
and then you`ll go your own way
you know you let your chance go
when you left me at the station
don`t make yourself at home here
you know you ain`t staying
you telephone your mother
and tell her where to reach you
come and get you in the morning
and not to bring a preacher

I said:
All right,come in you`ll get pneumonia
you can stay until the morning
and then you`ll go your own way
you know you let your chance go
when you left me at the station

I said:
All right,come in you`ll get pneumonia
you can stay until the morning
and then you`ll go your own way
you know you let your chance go
when you left me at the station

My,my
what you waiting for
what you crying for
oh girl
got me in the rain

All right,come in you`ll get pneumonia
you can stay until the morning
and then you`ll go your own way
you know you let your chance go
when you left me at the station

I said:
All right,come in you`ll get pneumonia
you can stay until the morning
and then you`ll go your own way
you know you let your chance go
when you left me at the station

I said:
All right,come in you`ll get pneumonia
you can stay until the morning
and then you`ll go your own way
you know you let your chance go
when you left me at the station

I said:
All right,come in you`ll get pneumonia
you can stay until the morning
and then you`ll go your own way
you know you let your chance go
when you left me at the station