I don't think I could do the irregular shifts that you work. I think that is part of the problem. However, since that is the nature of your job and you want to keep your job, you have to work around it.

I agree with making a list of everything you need to do to get ready. Time everything one day and put the time allowed down next to each item on the list. Then, you have a realistic idea of how much time you need. Then, add some padding to that and start getting ready at the appropriate time to be early (15 minutes or so). Finally, use a timer for each task on the list to keep from getting distracted.

I actually used to do this with my ADHD son to keep him focused on getting ready for the bus and also to get homework done.