So you are having issues with living with the family. I can tell you, that going away to college was the best thing that ever happened to me. Relationships with my mom and dad improved dramatically,and it was because they didn't have to bicker at me for the small stuff.
Unfortunately my eldest sister (I am the youngest of 4) wasn't so lucky. She went to the Local University and was guilted into staying home. As a result, he grades slipped, she dropped the med program, and pursued another major.
Eventually her solution was to spend more time at school, in the library, out with the friends. She developed a hobby, took on a job, and even took us out for a movie every now and then.
The key is that you are stressed because you are living as an adult, in a household where you were predominately a child for the majority of your stay. The solution is to get out. And if that means with your boyfriend, great!...But respect the idea if he's not too cool with it. Meaning, you need to think of other options for housing. Can you perhaps seek student aid?
Are your grades good enough to get scholarship money to aid the costs of any other housing expenses.
The problem that I saw with a few of my roommate live-in girlfriends is that they adjust too nicely. They make the apartment thier own. This scares a guy as much as seeing tampons in his medicine cabinet.
Side Story: I once caught my girlfriend putting her toothbrush outside of her allocated slot in the drawer. When reaching for my Motrin one day, I noticed this, and quickly addressed the issue that though I loved her presense, she was merely a guest, not a permenant party.
Point being, if you do happen to go through with this move in, allow your boyfriend the latitude to make rules. And yes, he may be great enough to say there are no rules. Bull * * * *! Make him set guidelines and boundaries.
The last thing you want to do, is alienate him, and more importantly stress the relationship by bringing problems home...to his home!
Lastly, if the Boyfriend is so supportive, it is my hope that he understands the seriousness of this issue. That being said, respect his decision regardless. And always look at it from the other point of view.
~John
IF this helps feel free to message me with any other issues.