Sounds as though it is suffering from stress, not too surprising in
veiw of the poor spring and cold weather when we are usually expecting
better. I would just leave it, amke sure it is well watered and it
should recover. Most fruit trees will drop their fruit the first year
after planting, don't forget the flower buds were formed while it was
growing with a good root system and was established. Now it is in what
to it is an alien environment that it has to get used to. First thing
to go is any fruit that may be forming.

Mike