If it happens once is it abuse?

This is my first time posting but something is playing on my mind and I can’t seem to get past it.
I have been married since I was 20 to a man who I love very much.

He likes to have sex every other day minimum which is usually ok. 3 years ago , when I was unwell, I didn’t want to. I said no, and he forced me. He continued even when I was crying.

This has not happened again.
I told a friend and she said I should contact a domestic abuse organisation to seek therapy , but I said it’s not abuse, as it only happened once.

However , I am having anxiety and panic attacks often. I don’t know what to do. Does anyone have any advice? What should I do?