How to Mentally Prepare Yourself for a Funeral
If you're a part of the deceased's family, such as a child or spouse, this is going to be a hard day for you. Don't worry about controlling your emotions, every one will understand how you're feeling.
Before the service will be okay as you're worrying about the flower arrangements and setting everything up. However, after everything is done and you're left to greet people, this is where it's the hardest. Try your best to keep it together. There are going to be certain people who talk to you who will be more choked up than you. If you need to take a break, do so. If you have a brother or significant other to help support you, let them comfort you as best they can.
For me, the funeral for my mother was two months after she passed, so I had already gone over a million ways of how it would go and how I would react. The ways I imagined it going were worse than it actually turned out to be. If you can, try not to stress out about the service beforehand, but know that you will get through it. It'll be hard, but after it's over, everything comes to a close. You'll have closure and will then be able to start healing and doing your best to move on.