First day of work, and I struggle to focus

I started working on my dream job on Monday (making games) but I just can't focus and I find myself so stressed and taking a lot of breaks, I'm not sure if this is normal or not, I just feel guilty for not giving my best, I struggle with keeping my mind out of worries of money and finance and stuff, I never felt this much stress or pressure, I'm just hoping I can do better next week, I'm not sure if I need to improve my productivity or need to take care of myself mentally, I'm just really worried about my mental health and my performance at work, it's my dream job but I feel so overwhelmed by it and I think it's affecting my focus or I just can't adjust to the routine and I struggle to focus during the 8 hour shift, I've always been bad at time management and stuff, but I really want to do better and keep this job for as long as I can.