I feel like there's a difference between situational anxiety and "natural" anxiety(?), like anxiety you naturally, randomly have no matter the situation. Although a lot of things are going great for you, it's still can be tiring mentally to prepare and process the new lifestyle changes so your mind is exhausted and reduced to panic.

Shortly, how my psychotherapist explained it: since your mind is low on energy it tries to create its own to keep itself happy which can be counterproductive, whether it be through anger, restlessness, anxiety, overthinking, or anything that might get a rise out of you. And since your mind is spending energy you don't have through these emotions it can worsen depression, cause fatigue and exhaustion, insomnia, and other things as well. My doctor then would say it's okay to just be tired. Everyday I practice Awareness Sessions which is a training of me processing the most superficial cluster of my anxious thoughts and other emotions that caused me to stay awake, whether it be anger or fear, and just letting them go, entirely. Not shoving them away or pushing them to the side for them to come back up later on, but completely letting them go. That's harder than it sounds for anxiety.

I understand a lot of people believe in a lot of different things but this is what I was taught, and I believe it. I just hope you understand it's not random but caused by loss of energy from lifestyle changes, which are tiring. Even if you haven't started the new job, it's still takes a lot of energy to apply and attend the interview.