May be fermenting, as they did in ancient times before fancy yeast and chemicals. Jesus and the people of his time just put the juice in clay pots and after time, " Wine". I would clean off the top of the cap and taste. After 2 weeks it should be approaching dry, if it tastes like wine take a gravity reading and move to secondary. May be low in Alchohol if you did not add sugar, maybe add some and leave in primary for a few more days. Mistakes like this often add up to a great wine HAHA