Can you get health insurance through your school? When I was a student, I used my university's student health insurance, which was fairly affordable and enabled me to have good diabetes care. if you can't get insurance through your school, is it possible to get a part-time job that will offer benefits? i know how difficult and time consuming school is, so i understand if that's not a possibility.
typically, when you first begin on shots. you are on a "fixed carb" diet, meaning at every meal you take the exact same amount of insulin and eat the exact same amount of carbohydrates. eventually, after the insulin has been properly adjusted, they'll allow you more freedom to eat what you wish and adjust your insulin accordingly.
i take it they only gave you one kind of insulin? typically, you need both a long acting insulin (one you take only once or twice a day) and then a short acting one (one you take with meals and/or snacks). it really is quite unrealistic of your doctors to expect you to never eat snacks. AND as a dietitian, we don't recommend just 3 meals a day. we either say 6 small meals or 3 meals and 3 small snacks. not many people can only eat 3x a day and not feel hungry in between.
your doctors are being silly, but i suppose it isn't their fault because they don't specialize in diabetes care.
you may also be a LADA diabetic (someone diagnosed with type 1 as an adult, who goes through a long period of time where they're still producing some of their own insulin. also called a "honeymoon" period). this means you may not need a whole lot of insulin in the beginning because your body is still kicking some out. i know that you don't have insurance, so blood testing often may be difficult, but do it as much as your prescription (and wallet) will allow. that will let you know if you are taking enough (or too much) insulin.
there are also LOTS of resources out there for diabetes help. if you google "free diabetes supplies + your city" you can find lots of local resources. or you can google something along the lines of "diabetes supply assistance + your state". also, a lot of the diabetes companies that provide test strips, glucose meters, insulin, etc also offer ways to get free or discounted supplies. you may consider contacting them as well.
good luck. please continue checking back in here, so we can help you out as much as we can! i'm so glad you found us here on juvenation. we are happy to have you around :D