I've been cross-examined. For ages. Very different circs though. I got through it by just focussing intently. Didn't look at anyone except the barrister questioning me, and the judge. Didn't think about anyone or anything else. It was very tiring, but my mother helped by saying 'Oh, they're only people, not superhumans. Just imagine the barrister naked and sitting on the loo.' I laughed it off when she said it, but I remembered it when I was in court. It helped that when the barrister stood up to start cross-examination, I noticed his flies were undone. Small psychological advantage to me.
It's all about taking your time, and not caring what ANYONE in that courtroom thinks of you, unless it is to remember that everyone on that jury is thinking 'Christ, rather her than me, I'd be terrified'.
Don't think about what any one answer will mean for your case, just give the answer. For me it was all about getting through until lunchtime, then after lunch all about getting through it until the end of the court session, and the same the next day and the day after that. I never thought further than max 3 hours ahead.
Provided you are doing your best to tell the truth (keeping your temper, taking your time, concentrating, being clear, including about whether or not you can remember stuff), and the judge will know if you are, then no one can do anything to you. I told myself that all the time-'the truth will set you free' etc.
I knew win or lose I could hold my head up, and so can you.