There are often confusions on using used to + infinitive and be/get used to + gerund. These two are used in absolutely different context.
USED TO
We use used to to say that something existed or occurred repeatedly in the past that is no longer true.
Sentence structure:
Subject + used to + infinitive(base verb or simple form of the verb)
Examples:
I used to drive on the left side of the road.
She used to live in a big city.
They used to work long hours.
We use ‘did not use to’ to express it in the negative form. There is no need to add ‘d’ to use as did is already in the past tense.
I didn’t use to drive on the left side of the road.
BE USED TO
We use be used to indicate familiarity with something or a habit. Being used to something means it is not something strange or new to you.
Sentence structure:
subject + be +used to + gerund
Examples:
I am used to driving on the left side of the road.
She is used to living in a big city.
They are used to working long hours.
The negative for be used to is ‘be not used to’.
I am not used to driving on the left side of the road.
GET USED TO
This is related to ‘be used to’. However, ‘get used to‘ talks about the process of the subject becoming familiar with or getting accustomed to something. It could mean that the subject has just started doing something and is expected to it regularly/more often in the future.
Sentence structure:
subject + get + used to + gerund
Examples:
I am getting used to driving on the left side of the road.
She is getting used to living in a big city.
They are getting used to working long hours.
We use ‘not get used to’ to say it in the negative form.
I am not getting used to driving on the left side of the road.