sorry for, sorry about, sorry to?

Sorry is an easy word, right?  Well, i'm confused how to use it. Would someone help me out?

i mean how to use " sorry for, sorry about, sorry to"? 

thx

1. My cat died. 

Oh, I feel sorry for you.

2. You hurt my feelings.

Well, I'm sorry about that.

3. You made me angry.

I'm sorry.

Hope these examples help.  You never say 'sorry to'. You are sorry, sorry about or sorry for. 

....and what about excuse me?

I stamp onof a person's feet.

How can I apologize to him?

I'm sorry or excuse me or it's no difference

or  I didn't understand a word's person

I tell him….sorry? or…excuse me?

1. Sorry for the small things that I did to you.2. Sorry about what had happened lastnight. 3.sorry to say that I need to leave soon.

Sorry I ddn't meant to do please forgive me

Thank you anothershadow, you were very clear

you also use EXCUSE ME when you will ask somebody smth..eg: excuse me.how can I go to the post office?

Thanks my poet, I've got it