The word ‘can’t’ is contraction for ‘cannot.’ Combined with ‘help’ you are communicating something you are unable to control or having a hard time gaining a grasp for. This can be a physical or mental action.

Here are some examples:

I can’t help thinking about it.
I can’t help shopping so much.
I can’t help working all the time.
I can’t help smiling when I see her.
I can’t help eating so much.
I can’t help loving you.
I can not help biting my nails when I am nervous.
I can not help smoking when I have been drinking.
I cannot help feeling so sad.
I cannot help remembering the things you did.

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