Not paying a credit card bill?

I had a mastercard gift card with 25 dollars and I signed up to this website because it was offering a 1 dollar trial for a day but what i didnt know was that it renews every month and charges you 35 dollars a month and well I didnt know that and Theres no cancellation option and the gift card only has like 13 dollars left and im so nervous that something might happen to me haha so can someone tell me if anything will happen to me? like get charged? or billed or something