@FIRE Me: I do love reading. I just like having the physical book. I fail to see how that affects anything in my question though.
Because buying and keeping scads of books means money out of your pocket, and it can start adding up (and also take up more space - I have a freaking wall of books right now that I need to reduce; it's ridiculous how much room they take up). The library has physical books that you can read and not pay for... so it's a win/win. Once you start collecting stuff, it's a slippery slope (not saying never buy books, but if you start buying lots of stuff now while you make so little, it is going to make a dent in your savings and cause you to have that much more stuff to store and haul around).
There's nothing wrong with living at home for a few more years, especially if you are saving tons of money by doing so (and not feeling uncomfortable with living with your parents). Living on your own - even with roommates is going to wipe out your paycheck right now since you make so little. Rent, utilities, groceries, furnishings (even if using craigslist/thrift stores), renter's insurance...
Do you have school loans? It wasn't mentioned, but you hedged a bit on your expenses it looks like as you said your only "main" expenses... if you don't have school loans, that's great, but if you do, it's an even bigger incentive to live with your parents for another year or two and pay aggressively on those, while building your savings.
You totally can ask for a raise after your first year, and if you know you do good work for them, do ask. And keep your eye out for other (better paying) jobs while you're working there. You never know when something will pop up.
And I wouldn't move any place until I had a good job I was sure I wanted to stay with for a while (more than a year or two anyway). Right now, you have a bit of a commute, but you have the option of locating a job that might pay much better just about any other location, and could move if you got it with no notice. That's a good thing to have that kind of flexibility.
Also since your girlfriend is still going to college for several more years, I honestly would consider that the timeline to getting your own place; when she graduates and gets a job, what about finding an apartment together near both of your jobs at that point? You should have a good amount saved (and I do hope you're taking advantage of any 401k if available, and investing in an IRA if not) and be in a much better state to find a higher paying job by then as well if you don't have one by that time.
If your sanity is affected by living at home (as you stated) is it just because you feel like you should be out of your parents' house by now, or because there are issues with your parents - abusive/no boundaries/hostile? Because just itching to move for the sake of moving (because you're an ADULT now dammit) is kind of an illogical reason - you know you're an adult, but you don't have to throw away your very meager salary to prove this do you? Because that's what you are proposing.
I get wanting to go out on your own and be your own person, but logically, you are in a great position to saveSAVEsave and still have someplace safe and comfortable to live. And I assume you're young, so there's still going to be plenty of time a few years down the road to get a place of your own. ;)