We recently got a cat, dog now refuses to eat when I’m in the house in the mornings

About two weeks we recently got a kitten. Understandable it’s been an adjustment for our 1 1/2 year-old dog and we assume he’s been under stress and has seemed less enthusiastic to eat. The kitten has constantly been trying to eat the dog’s food and we keep telling it to not do that and pull it away from the food.

Earlier this week I served my dog kibble with boiled egg as a topper (one of his favorites), he flat out refused to eat it and starting trembling when I kept trying to encourage him. However, he ate when my girlfriend came home in the afternoon. The following day I served him and again he didn’t eat. Shortly after I left to take the kitten to the vet and I returned to see that our dog ate his food. The next day I served him, didn’t eat when I was home. I left and realized I left my cell phone back at home. I came back to see my dog was eating. Yesterday, both me and my girlfriend were home in the morning and I served the dog breakfast, again would not eat. My girlfriend encouraged him to eat and he still wouldn’t. However I left and that’s when he finally started to eat.

Today, he refused to eat when I served him and tried to again coax him. However he’s now eating when my girlfriend encouraged him (at least I didn’t have to leave the house)

And this problem only happens in the mornings, he’s more willing to eat in the afternoon, and he’s still accepting treats from me when offered.

I really hoping for some help to understand what maybe my dog is feeling, what I can do to maybe regain his trust again? Maybe anything that I’m doing wrong?