How much sugar did you add? This seems really unlikely, but fresh pressed juice is full of wild yeast, so maybe it fermented a lot in the first couple of days.
Most cider seems to be around 1.040 or a little above, in my experience. So if you had 1.040, fermented to 0 ("no reading"), that's 5.25% alcohol. Then you added sugar and got a reading of 1.030, which fermented to 1.020, adding 1.3%. That's 6.5% and sweet, which might taste boozy and kill your bread yeast.
And your original gravity (OG) could have been higher than that.
Wild yeast can keep going probably but maybe not?