Anxiety in the middle of the night

So me and my boyfriend live together. And generally are very happy.

Even though I struggle with my mental health sometimes.

Last night we woke up in the middle of the night to have sex. Not unusual and it was great.

But afterwards I just could not get back to sleep for about an hour and a half. It was like I was having a panic / anxiety attack. I had to really focus on my breathing for it to not get out if hand and had a horrible twisting in my gut.

That’s never happened to me before.

Not sure why I’m writing this. Most of the time I know what triggers my anxiety but I don’t know this time.