That happened to me on the 300K. I was all stoked about having a tailwind back. Not.

For the original question, I'm about the same as you with speed. 18-22 on a flat. When I'm going into say a 10mph wind, I drop to around 17. If it's stronger, say 15-20mph, I drop to like 15. So if that's being out of shape, I'm right there with you I do try to get down into the drops when the wind is blowing. I gain a mph or 2 if I do that.