You're screwed now if that nut comes off the bolt because the bolt will simply drop out. If it does come out you will loose control of the car. There is a reason the bolt points downward and the nut is on the bottom. It is the same reason the bolt is under the spring (so it will not bounce out if the nut does come off). I suggest that you find a way to get the spring up high enough to reverse the bolt ASAP. In the mean time check the nut EVERYTIME you begin driving the car. Also check it every 5 miles or less.
I'm sorry you took the idea of not removing the spring to the point of reversing the bolt. The way to remove the bearing without removing the shaft is to leave the nut in place and simply turn the bearing itself by the adjustment point until it comes off the end.