I have some advice for you: turquoise staples. They brighten anyone's day. If you ever find a box of turquoise (or chartreuse, or fuchsia, or whatever does it for you) staples, especially if they're on sale really cheap, they make an excellent impulse purchase. Months later, when you've had a shitty week and you're also filling out your income tax return (which, perhaps, may be slightly cheering, because you're getting more money back than you thought, except, damn, you'd have filed two months ago if you'd known that), you can be putting together your return, and stapling your W-2 to the appropriate edge of the form, and... hey! The staple is turquoise. If it takes more than that to amuse you, I don't know what to say.
You could also get whatever weird stamps they're selling, next time you need stamps. It is not entirely unsatisfying to have a sheet of weather stamps, and send your tax return with Altocumulus undulatus instead of, you know, LOVE.
You could also have a little sponge dinosaur (you know, one of those sponge creatures that grows out of a little capsule you put in a glass of water), and use that to moisten envelopes instead of licking them. (Okay, it's Ken that has the dinosaur, not me, but I gave it to him.) Licking envelopes is kind of gross anyway. When you're done making the dinosaur lick your envelopes, you can wave it around at your girlfriend and say, "Grrr! I am Lickysaur!" Actually, you could possibly do that without the dinosaur, but it would be slightly different.
As weeks go... I've had worse.