Oh, sweetie - there is no greater invasion of privacy than sharing your body with another human being! I know there are women who find pregnancy to be a wonderful state of being. - and more power to them. I personally found it to be an absolute violation. Totally, completely, utterly worth it - but still a royal uncomfortable pain.
As for the shower - honestly, if you have what you really need - let people give what they want. Better yet, what do you think about expanding that registry to include some cute little outfits, books, hooded towels that YOU like. It seems silly, but nothing is more fun than a shower where all these adorable little baby things get passed around and each and every woman present gets a chance to "oooh" and "aaah". It's about the party and the love in the room, not what you go home with. Of course, you already know that, but is DAMN hard to remember when your hormones are a mess, and you have to pee every 2 hours and even if you didn't have to get up in the middle of the night to pee you can't really get comfortable in bed anyway, etc. etc.
PS Keep eating those tacos! I am a firm believer in the spicy-food-speeds-delivery theory!!