Did anyone experience a low mood after starting this healthy eating routine?

Hey, I'm new here, I've been following this plan for about 4 days, pretty strictly because I'd like to lose a few pounds before my wedding. Before my routine was ok, I'd eat 2 healthier meals in a day with a small supper but I wasn't losing any weight and maybe working out 2x a week. I feel very overwhelmed and have a low mood, but I'm determined, I'm wondering if anyone else is going through this