you need to chill a little Stripes.
you moved into your house so you could have your own space, with that came the cost of paying the rent by yourself.
your girl lives with her folks, that's her space for her reasons
She is hangin with you when you are in town, that's fantastic, obviously
for her to buy the groceries is a bloody bonus dude, not something that should be expected.
as Fluff said below, its only been a couple of months, you can't expect a person to move in permanently so soon