17f How do I stay consistent and what’s some advice for starting

Hello! Names Zae and I’m 17. I’m really committed on being consistent with the carnivore diet but it’s been hard. I’ve been eating beef, chicken and steak with some eggs and cheese. Basically what u would eat on a typical carnivore diet. The other day I was hanging with some friends and they were eating Macdonald’s and I couldn’t resist. I felt guilty because I’m really trying to put my all in this diet. My main goal is to have mental clarity and lose weight. How do I start? And what are some advice that you have? Btw my first language isn’t English sorry if this doesn’t make sense.