Whoa whoa!

It's ok. Everyone has to learn sometime. This is how you learn - you do it, you make a mistake, and you go ... well, I won't do *that* again.

And it's better to learn NOW, while you're young, and to build healthy habits. It's much harder to change them when you're older.
A few things for you - while I understand wanting to eat all organic, it's MORE IMPORTANT TO FUEL YOUR BODY! So if you're on a really tight budget and the difference between buying organic and buying regular means you get enough food to eat, don't buy the organic. A 5lb bag of regular apples you should be able to get for around $3.99, whereas you'll pay $3.99 for a pound of organic apples. In this case it's better to buy the non-organic and have food to eat.
I would suggest you make a plan for your meals - at least until you get the hang of what is enough and what is too much. I have been cooking for 30 years and I still plan my meals out on Sunday so that I can go grocery shopping either Sunday night or Monday evening. I rarely go shopping w/out having a meal plan first or I wind up not buying enough food, or not buying the right kind of food.
I've posted a link to my plan before, which I lay out in an Excel spreadsheet. It contains my meal plan for the week, plus my shopping list which I build from the meal plan. It looks like this:
You don't have to use Excel. You can do the same thing by making a chart on a piece of paper. But the idea is to plan out every meal and every snack and then use that to create your grocery list. If you know that you're going to eat a turkey sandwich every day for lunch, then you know you'll need 1 lb of sliced turkey (1 lb of turkey has about 7 60g servings). If you know that you are going to make hamburgers for dinner one night, you know that you'll need about 1/2 lb of burger for 2 people (that'll give you each 4oz of meat). Etc. So you can figure out what you need to buy.
And it'll also help you budget because you won't be buying things and then trying to figure out how to use them.
Speaking of budgets: When you're on an extremely tight budget, buying things like granola bars is a bad idea. Those types of convenience foods are some of the most expensive things you can buy. Far better to buy a box of oats and make your own oat bars if you really want them, than to buy them prepackaged. As well as being cheaper, they'll be healthier if you make them because you can control the amount of sugar. And of course, there won't be any preservatives.
Planning will also help with the issue of not having time to prepare something becuase you're running late in the morning. I've posted this before, but every Sunday I boil a dozen eggs. I make 5 1/2 pb sandwiches (2 T pb on 1 slice whole grain bread, folded over, and put in a ziplock baggie). I portion baby carrots out into snack baggies. I divide my yogurt out into 5 individual containers. I slice a block of cheddar cheese into 1 oz portions and put them in ziplock baggies. I count and set aside string cheese. If I've made something like hummus, I portion it into 5 small containers. If I have apple sauce for the week, I portion it into 5 small containers. If I make oats in the crockpot, I make them Sunday during the day and then portion them into 5 containers. Basically anything I can do Sunday night to make sure that in the mornings I just grab 4 or 5 things and throw them into my bag ... I do it.
Then every night I slice an apple and put it in a ziplock baggie. I fix whatever I'm going to have for lunch the next day - whether it's leftovers from the night before, or something fresh. I put it in the baggie, or the Tupperware container or whatever. I have a shelf in my fridge that is *just* for my food that I take to work and it all goes there. That way in the morning, all I do is grab stuff, throw it in my lunch cooler, and leave.
Planning, planning, planning - it's hugely important especially when you've never done this beforea nd you're just learning what to buy and what amounts to buy it in. At some point you may find that you don't need to plan this strictly any more or that you want more flexiblity, and that's fine. But for now, I think you'd benefit from really planning out your weeks ahead of time.
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