If you are getting emotional on the stand, stop, take some deep breaths, have a sip of water, and continue when you can. If you need more time or just need to reset, ask the judge if you can take a short break. 

The biggest mistake I made was thinking I could be as productive as I usually am the week of my trial. I usually direct my anxiety toward getting schoolwork done but I couldn't do it. If you can, I STRONGLY suggest you ask for extensions and time off. I won't lie, it will be incredibly draining both emotionally and physically and the last thing I wanted to do was force myself to work on assignments. 

Showing emotion and crying on the stand is not a sign of weakness. You being there, standing up and testifying shows just how strong you are. 

Throughout the week, no matter what, remember that you are not the one on trial. 

Be kind to yourself and notice your self-talk. No one is a perfect witness. All you need to worry about is listening to the questions and answering honestly. 

As someone who needs to let off some steam after a stressful event, I booked a time slot in a Rage room. It is a safe environment to let out your anger and there is something cathartic in smashing a bucket of plates after a very difficult week. 

This might sound cheesy but it really is a marathon and not a sprint. I suggest you get on a good sleep schedule and start focusing on self-care at least a few days before the trial. You don't want to show up to testify exhausted or hungover. 

Don't talk about your testimony with anyone until you have finished testifying. You can talk about the case once the judge excuses you and your testimony is concluded. However, if it is a jury trial, you cannot speak to any member of the jury at any time. If anyone tries to get you to alter your testimony, tell the Crown attorney or the police right away. Harassing or attempting to influence a witness is a crime.