I felt the exact same way as you a few months back...I don't have an obsession??. But the more I read and the more I thought about it the more it became obvious I do obsess over interests I just don't have lifelong ones like some of the info suggests aspies do.
At the moment my two main obsessions are baking - cookie/cake decorating and my daughter's birthday party. I saw an advert for a new baking magazine and thought "wow that looks so interesting" So I bought the first issue and read it cover to cover over and over, was desperate to get started on baking and it just developed from there. Soon I was watching videos about how to ice cupcakes, how to make sure your butter doesn't curdle when mixing. I was looking up various tools to buy, I ordered loads of cookie cutters and of course made lots of cookies and cakes.
My daughter's party is something I obsess over every year, I LOVE the planning of it all, thinking up tiny little details to make it amazing. The past few days I've trawled the net looking for the perfect fairy wings and pink shoes to go with her dress. I ordered some fairy cookie cutters, I've been looking for the right fairy themed tableware (she's having a
fairy school party). I make lists of the food we will buy, check the prices at various stores online to find the best deal. Earlier today I was measuring how big the marquee they bring along is so I can work out exactly where I want it, where they can do the photoshoot etc. And if something doesn't go right or if for example I'm outbid on the perfect pair of wings on ebay....I rage and cry. I was in a complete state because the booking clerk hadn't got back to me about whether she'd booked us in for the hall on the right date, I'm still worried about that because she hasn't sent me the form to fill in but I can't keep pestering her or I'll look like a lunatic.
I also completely understand when you say you get disappointed and give up, I get like that all the time, my baking obsession has come down a notch after I had a complete meltdown because my piping bag split and then I ran out of icing and the cakes didn't come out exactly how I'd planned so it kind of ruined it for me.