I think sometimes this can happen. I've had a few experiences like that over the years. One minute fine doing whatever, then it's like you lose all energy and feel wretched.. and then you feel worse when it's somewhere public (like a supermarket!) that you're going to puke and you don't have a bag handy or anything and don't want to create a scene, let alone doing it etc. And of course if you're with someone there's that feeling too. It could have been anything - sudden drop in BP, maybe a smell in the aisle set some kind of tummy reaction off.. anything. I'm sorry that happened.
i remember one time a few years ago (this is a bit different, but it was very difficult for me) I was at the airport. I had a plane to catch. I wasn't late, but I didn't have much time.. so there I was, running (well OK, fast walking) through the check-in area to get to departures for my flight and I swear right in the middle of the floor I.. just.. stopped. I mean literally came to a grinding halt. I didn't fall over but I couldn't move. I just had NO ENERGY. It was one of the scariest things that I ever experienced. Then I started to get into a blind panic because I thought "oh crap. What is this??!!" I didn't feel sick per se, just like someone pulled my batteries out. I was stuck for a few minutes before I could move again. I'm sure I looked quite the site just sort of standing there probably looking either lost or terrified!
Nobody was with me at least. Luckily it only lasted a little bit and I was able to move, but slowly, after a couple of minutes. I made my plane OK but was a bit shaken... but I was fine for the rest of that day, and never had a problem like that since. I think it just reminds me that things can and do happen - some of them you just can't explain.....
At least you have your new furniture on the way and Blokey is better. These are things to celebrate!