Congratulations on four months for you and your girlfriend.
I think it's very well explained by mld51's post.
I've been sober ten years, and I still get bored. But, I'd much rather be bored than drunk.
Hang in there, you'll find something to pique your interest. Find something you enjoy doing. There's a million things that open up to us when we stop using, you just have to be willing to find them.
What have you always wanted to do but haven't? Try it.
Best to you and you can always come here if you're bored.