Those receiving Carers Allowance should have NI credits called HRP.
The government now accepts that it has massively mucked up credits over a long period!
Be sure to check your records! (This is such an important issue perhaps CUK could find out full details and publicise the full details. There will be many former carers affected by this!)
There are also Carer Credits for anyone not receiving Carers Allowance but who are providing over 20 hours a week of care. Takeup of this is extremely low.
To check your NI payments/arrears use this link
NI - national insurance payments contribute to your state pension and gaps will affect your pension.