Why am I anxious at night before bed?

Most likely it's because it's late and you are tired and ready to go to bed and usually thats when anxiety hits, for me at least, you are just alone in your own thoughts.

Thinking about the day to come and what happened during the day. If i messed up i will worry about what will happen

While you are trying to sleep, your mind is not being occupied which makes it easier to have anxious thoughts. It is helpful to assure yourself that non-pressing matters can wait until the morning.

I tend to think a lot before sleeping too. Mainly because we spend the day doing so many things that we don't have time to sink into our own issues or to try to deal with them. And before sleeping is the only time those thoughts start creeping into our head.

I find it to because I am so worried about being alone in the dark with all my thoughts that I get myself worked up in case I can't sleep which is a largely irrational fear of mine.

At night your body is naturally more relaxed and tired as it prepares for sleep, also by producing hormones that contribute to it that are not segregated during the day. At the same time, unfortunately this give your mind plenty of time and opportunity to focus on all your worries, negative emotions and problematic thoughts, some of which can drive anxiety. Particularly when you are in bed, the above mentioned factors can become out of control and form a vicious circle, which in turn can bring the anxiety to increase to the point of not letting you fall sleep or even sleep at all.

During the day it is easier to distract ourselves, but before we go to sleep those distractions tend to end and our thoughts get a chance to get a word in edgewise so to speak - they demand to be heard after having been ignored all day. That's why it is so useful to give them space with mindfulness practices or journaling. If they are not acknowledged and dealt with they can keep repeating and endless ruminating is not the best recipe for a good night's sleep that would be very healthy to one's mental health. Listen, deal, move on.

There are several candidate reasons. I assume your anxiety is making it difficult for you to fall asleep. Before you go to bed, perhaps you engaged in activities to distract yourself from your anxiety (such as scrolling through social media, playing games, etc). When you go to bed, you are no longer distracted, and so you feel anxious. Your anxiety may be stemming from current problems in your life. You could try undergoing structured problem solving to solve your problems, so you wouldn't need to worry about your problems anymore (https://www.blackdoginstitute.org.au/wp-content/uploads/2020/04/16-structured-problem-solving.pdf). You could write down your worries on a notepad then address them tomorrow. Or you could engage in mindfulness meditation to let go of these worrying thoughts. Your anxiety may be stemming from sleep worry, which is worrying about the consequences of not getting enough sleep. Most people with insomnia catastrophise the effects of being sleep deprived, and have beliefs like "If I don't sleep well, I can't function normally". When such thoughts are seen to be unrealistic, people with insomnia have an easier time falling asleep. Forcing yourself to fall asleep makes you more anxious and keeps you awake - understand that sleep comes when you stop trying to sleep.

Anxiety affects sleeping by definition. It is actually common for many anxious people to have trouble falling asleep, because stress works this way. I understand that this can be annoying, because sleeping is supposed to be the time during which our body and mind releases all day's tension. What I want to tell you is that it is not your fault that this happens. If you have to deal with many different tasks during your day, you might find it dificult to fall asleep. Try to not think much about it, if possible. There are also many great breathing and meditation exercises here on 7 cups, you can give them a try if you want. I hope they help you.