Been over calories frequently

I've lost 85 of the 110 pounds I need to loose. I wake up at 6am for work and don't get home until 6pm and usually don't have energy to go to to the gym, and if I do it's late at night. I try to stay under my calories during the week, but the weekends I'm always a bit (400-700) calories over my goal. My current goal is 1550 and if I eat less than that I always feel tired. During the weekend when I eat a little more I always feel like I have more energy. Should I feel bad that I eat over on the weekends? I don't know what to do about this, and I don't feel good anymore that I'm eating 1550 calories or less.