Time off for IUI

I have been trying to conceive for last 4 year, I went to see a specialist and was planning to have IUI. My work is not flexible and is not easy to predict when to take annual leave as my period is not alwas regular.The fertility clinic is not flexible either.This  brings lots of frustration and anxiety. My work doesńt know that I am planning this treatment. Am I the only one or is there anyone else who had similar problem? :(