Hello jmb, I don't know about if it gets better or not but it is my personal hope that eventually it will go away. But for now I've learned to enjoy my ups and to prolong them a little bit.

About your sister's shower... I've been to an engagement party and two weddings when I was extremely depressed and I couldn't even walk without pain back then. (Weddings are a two day affair for us.) On the second day of my cousin's wedding, I was in so much pain that I took the meds without a sufficient food intake and had to excuse myself for the rest of it. She never held it against me.

Its just something about the atmosphere when you are there among all those people, a little of it infects even yourself. Even if you don't talk much or participate much, just being there is enough to make your sister happy, even if its only for a little while. She knows that you're having problems and that you've come despite of that will mean a great deal to her. That itself will make you happier.

Keep a calm head and when you get there you'll cheer up a little even without realizing it.