Dear Suzanne:

There is no reason to feel guilty. There are no regulations, at least that I am aware, that requires using the right hand or left when receiving our Lord in the hand. You did nothing wrong.

I would recommend, however, that you consider not receiving in the hand at all. The universal norm for the Church is to receive our Lord on the tongue. Communion in the hand is a recent novelty that has been allowed by the Holy See to those bishop conferences who wish to allow it.

The history of this practice of "communion in the hand" is a negative one. Here in the United States, the land of the biggest and most immature babies on the planet, the practice developed in disobedience. Priests were teaching and encouraging this practice illegally before it was authorized.

In my opinion, the reason that the Pope finally allowed the practice is for the same reason that any parent must pick their battles with their kids. Children in their immaturity will have all sorts of hissy-fits to get what they want. Sometimes a parent must weigh the cost of insisting on what is traditional or to let their children have their novelty.

The Pope, the "father", must have thought that since there is no real theological problem with communion in the hand, that it was just not worth fighting over, and thus allowed it.

This is the same reason why female altar servers were allowed, in my opinion. 

If the Pope had been strict on either of these issues, there would have been a hissy-fit by the big babies of America that could have been heard on the moon.

Since neither of these practices challenges any theological, moral, or doctrinal truths, the Pope decided to allow the practices as long as the faithful were properly catechized about it.

The only thing these two practices offend is the rich and meaningful symbolism of the tradition to which they evolved. But, that does not offend any dogma, doctrine, or theological teaching, and thus the practices are technically allowed. 

God Bless,
Bro. Ignatius Mary