I'm using this as proof I'm not crazy (well at least on this issue). I booked flights the other week. In the afternoon I priced out 4 different destinations, we picked one a few hours later, went to book the flights and every one was massively higher! I've managed to rebook one leg already to lower than the original price l found, just waiting on the other drop back. One destination was 22k RT, looked later that night it was 39k, looked the night I rebooked and I found a slightly different option for 11k RT
And none of the flights were the "only 2 seats left" at this price either, they just all went up; and I tried mixing up the searches with incognito and different devices but got all the same results. This is the wildest swings I've seen from what I remember, especially in such a short time frame.