I think you've hit the nail on the head, it's your day and should be treated as such - you should be permitted to do, or not do, as you wish.
On the gift thing, it can be a little awkward and, like you, I have particular tastes and needs so can be difficult to buy for as I also like to research and also know what I already have and what might compliment it. I understand that some people get enjoyment from the gift giving though, it makes them feel good to give them. I get it.
I'm going to accept the whole birthday thing and know there will be no cake and candles, no fucken singing and no one but the two of us, just the way I like it.