My parents aren't helping me prepare for college?

Im going away to college in just a little bit over a month and I am getting concerned because my parents haven't been helping me get prepared. Every time I ask to go out and go looking for stuff with my parents my mom says it is too early to start school shopping, or she changes the subject. I've been talking to other students and they said they have the majority of their stuff already (including their text books.. which I haven't gotten yet).

So in result of my parents not going out shopping with me, I've started to go out by myself and buying everything myself with my graduation money and money I have been earning all summer. Every single time I get something my mom says something to the effect of stop buying stuff or she bitches about how she doesn't like it.

My dad is busy sometimes, but if I ask him to go somewhere, he will if he's not doing something that day. He doesn't really give me any input he will just follow me around the store.

Some back ground: Im the last child in the family, and I am the first going the traditional route to college. My older sisters are 32 and 29, one went to a state school 5 mins away and the other went into the military. My parents haven't "done this" in a while, so are they just not happy to see me go? Is that why they are not helping and my mother is trying to not let me get stuff?

Im frustrated because I don't like to not be prepared and I like to do things in advanced, I'm not sure what to do.