Need advises on eating better on a busy schedule

Hello everyone,
I just want to ask for advises. I keep falling off the wagon when it comes to eat healthy, be active and just have an overall good lifestyle. I go through phases where I eat healthy, I don't drink or smoke, I exercise and then I get a bit busy and it shifts my routine and go back to junk food, smoking, and not exercising. Not only it affects me morally, it causes me to play yo-yo with my weight. I have a very irregular schedule due to work and school so it makes it difficult to eat at the same time every day. Some days I am too busy to eat before 1pm so I end up eating nothing for nearly 6 hours, I bring gigantic amount of food and most of the time I barely eat any of it.

Anyone has tricks or suggestions for me to be able to eat more regularly while on a busy schedule?
I would really appreciate it.