Wait a sec- My original answer didn't address the underlying cause here. Did you just say that you're about to buy a HOUSE with someone you're NOT MARRIED TO? Are you NUTS???!! No wonder you can't sleep!
Of course I know nothing about how much in love you both are...but legally, this can end up being a real mess if you decide to split one day. (I've had friends who've deeply regretted the decision to buy a house w/ a boyfriend.) And boy, it's easy to split up with someone you're not married to. So either get married --or at least see a good financial adviser--and then maybe you'll be able to sleep at night!
Here's my original answer:
Are you eating enough protein during the day? Most women don't eat enough protein. Also, many women who want to lose weight are on a low-fat/low-protein diet, which actually doesn't work (if you don't have enough healthy fat in your diet, you end up craving carbs, which is what puts on the weight) but that's another story.
In any case, most women don't eat enough protein. Protein helps you sleep. Especially grass-fed, organic meat.
A hour before bed, eat a snack that involves protein. Apples and a couple tablespoons of peanut butter pretty much are my "sleeping pill."
If worry is keeping you up, keep a tablet and pen next to the bed. Write down your worry list and know that you'll get to it in the morning.