Hi Evie,
Don't worry, I have had times in my life where I used Reiki all the time and then 'life' gets hectic and I get distracted and it becomes occasional for a while :) I know it isn't ideal and in an ideal world we would do a full self Reiki everyday, but a little is better than none at all and I know that when my kids get older and life is calmer I will find more time. It's always going to be part of me now :)
The great thing about Reiki is that because it's part of you it's like learning to ride a bike, you don't really forget. Once you get started again, it will seem like you were never away :) Perhaps you could give yourself a self treatment before you share Reiki with your friend.That way you might feel more confident.
Gentle Blessings
Helen