A few days ago I had the gold Copy Editor badge on Stack Overflow for 500 edits. Today I don't. I checked the Data Explorer and according to that I have only made 100 edits. I didn't think badges would be revoked once earned, and even if they are I don't see how 400 edits can disappear so quickly.
According to waffles, the logic for getting the editing badges have changed. I guess the badges are being revoked and re-rewarded based on this logic. His comment below on that answer seems to confirm that.
The data explorer data is up to a month out of date so your edits for February won't count.
The queries on the data explorer tend to under-report edits as they only identify those posts where you were the last editor. If someone else edits the same post later, the fact that you edited the post is "forgotten".
The rules on multiple edits to the same post were tightened. You now have to make edits to 500 posts (which isn't quite the same). Source
So you probably lost the badge due to the last change, but you are closer than you think because of the 1st two reasons.