I Have Been On The Nuvaring For About A Year,

I have been on the Nuvaring for about a year, my periods usually lasted about 4-5 days, needing tampons 1-3 days. I used the Nuvaring and didn't take a week off because I wanted to skip it, the following period was VERY heavy, and the one after was VERY light. I only used liners for 3-4 days. I only use the nuvaring, no condoms, could I be pregnant?