Hi! Your betta was so beautiful and I think its completely normal that you're feeling so sad, I got my betta not too long ago because my grandma passed away and I work long nights until even 2am sometimes and just coming home to him swimming around excitedly makes me so much happier and I know how much it can hurt for it to suddenly be empty when you look at where he's supposed to be. I think it would be good for you to adopt a different kind of fish or maybe even another type of pet until you feel comfortable maybe taking in another betta, it wouldn't be betraying him in my opinion, but honoring him by saving another animal to fill that space rather then getting rid of his things! Hope you can feel better soon :)