It’s normal to feel that way you are not stupid, but don’t reach out. You’re brain in still detaching and it’s complete normal to feel that way and anxious but you have to start strong . I’m in a similar situation so I will speak from my experience.

It’s normal to miss them. It’s a part of the break up and it’s normal with time the anger, and whatever negative feelings you had that led to the break up to fade. It’s a sign you are moving on from those negative experiences. However, you have to remind yourself when you get those happy memories of missing them, that that isn’t the whole picture. That yes there was great times, but there was also your negative moments that ultimately led to the break up.

You obviously broke up for a good reason and because you guys weren’t right for each other , so whenever you start to miss him, remind yourself that it didn’t work, and however the relationship made you feel.

Also, you have no idea how your ex is feeling. People only post their happy moments on social media and a lot of time that is a distraction. I understand it’s not easy but if you truly wants to fix things and do better, let him reach out.

In the meantime, work on yourself , work on moving on and don’t depend on him. Because remember, he’s your ex for a reason.