If the prescription difference in the two eyes are not that big and you didn't get any infections during those 3 days, it is OK for your eyes. But you must change them back as soon as you realize this and try your best to prevent this from happening again.
It will depend on your prescription. Since you have different prescription in both eyes and you find things blurry, it is harm to wear the contact lens in the wrong eyes. You should change them immediate you realized it.