I'm following this meal plan where I eat 6 portioned meals a day with protein, carbs, and vegies with at least 2 of the meals. I'm doing good so far and it feels good to never be hungry. However, I start school next week and I'm not going to be able to cook all day. I figured I could eat things like sunflower seeds and peanuts for protein or pb sandwiches for protein and a carb. But that would get old fast.

I was wanting to cook and prepare food that I could microwave when I'm at school. Is it OK to do that? I mean that's what most packaged freezer food is like, already cooked and you're just warming it back up in the oven. Is there any specific way to do this or only certain foods you can do it with?

I also know someone who microwaves their eggs in the morning. That would save a lot of time. Does it thoroughly cook the egg?

I've microwaved eggs before. You have to be careful with the timing. A few seconds too short and they're runny, a few seconds too long and they are way over cooked. I've frozen food before to eat later. Make sure it's very well sealed. I suggest investing in a vacuum saver if this is a long term plan. It really helps protect against freezer burn. Otherwise some good freezer bags will do fine (and I mean the ones that say freezer, not just ordinary sandwich bags). Let the food cool before you freeze it.

I agree the vacuum seal or the freezer bags.
You can take them out of the freezer. With some foods you can put the bag right into a pot of boiling water until they are cooked.