Is there any expression sounds unnatural?

I remember it was when I went on a 2 days trip with my friends and their children.
We were having dinner at a restaurant serving local cuisine, and one of their children burst into tears.
His mother looked at his body. She found that he had hives on it.
We rushed him to a hospital. He was allergic to egg white, so he had to have an I.V.
Buecause his mother needed to take the other child to the hotel by car, I held him in my arms until the I.V. was over.
I couldn't move for about an hour and my arms weve tired.
After that, he got better and then his mother came to pick us up.