I Had My 2 Month Nur-isterate Injection On 11 November

I had my 2 month nur-isterate injection on 11 November 2015 - was due for next injection on 6 January 2016. End november i was in hospital for 6 days for kidney infection and failure and received anti-biotics and not sure what other medication. Did this cancel out the nur-isterate just for that period i was taking anti-biotics? Or was i unprotected up to my injection 6th January?

Also on 8th and 10th January i had intercouse, could i be pregnant? As i only went for my injection again on 15th January 2016.