Jyothi, thanks for explaining the difference between "caretaker" and "caregiver". I did not know this, and hadn't even thought about it before.
Smrithi, you ask great questions about tense that are making me think and research and learn too, so thank you!
"Got" is the past tense of "get", and because it is one of those irregular verbs, it is misused often. These are its most common meanings and usage (there are many, but I will concentrate here on just a few):
1) in place of "became"
I got seasick as soon as I stepped on board the ship.
2) to mean that something has been received, obtained, etc.
He got his driver's licence yesterday.
I got my full deposit back when I vacated my apartment.
Here is a link to a page that discusses the many uses of "get" (but not "got" specifically, so don't look at it if it will confuse you).
How to get to grips with the verb “get” - Englishonthe.net
Now, to your sentences:
1. I got used to it.
This is correct usage - "got" here is used to describe an action that is performed upon oneself. Another similar example in this category would be
I got married at a very young age. 2. Our flight got confirmed.
This sounds okay, but to be on the safe side, I would rather say
Our flight was confirmed 3.Tickets got booked.
I'm not really sure whether this is correct or not - it sounds wrong to me (even though it's exactly the same as the example above). I would rather say
Our tickets were booked 4. My contract got over.
This one, I can emphatically say is not correct usage. You should rather say
My contract is over
OR better yet
My contract has ended.
"Got over" seems to be colloquial Indian usage.
So, that's my trick for getting around language issues I can't resolve definitively - I just find another way to say the same thing that "sounds better" to my ear. If anyone else has a better understanding of the uses of "got", feel free to jump in.