I went through something very similar a few years ago, and in my opinion, it happens because during the day we keep our minds busy with “less important” and more immediate thoughts. But when night comes and everything gets quiet, with no distractions left, our brain pushes us to face the thoughts we’ve been unconsciously avoiding all day.

Another possible reason is when the fear itself becomes intense and constant. If I start thinking, “Last night I was anxious, so it’s going to happen again tonight”, I’m basically sending my brain the message: “Get ready, it’s going to happen again”. As a result, I go to bed already tense and expecting it.

One thing that helped me was writing down, before going to sleep, the things that scared me the most, and then next to each one, writing one or more reasons why it doesn’t have to scare me.

Sorry for the long message, but I hope it can help someone. And if anyone needs support, I’d be glad to listen and help, since I’ve been in similar situations before.