Hi Ariane Vasconcelos,
If you reach State Pension Age after April 2016, you need a minimum of 10yrs to qualify for UK Basic State Pension.
You can check your State Pension forecast at Check your State Pension forecast:
Check your State Pension forecast
As you have been living and working abroad, I would also advise you read leaflet NI38 which explains about the opportunity to pay UK Voluntary National Insurance Contributions whilst you are now living and working in Portugal:
Social Security abroad: NI38
You will not be entitled to a refund of UK NI if it was correctly paid.
Thank you.