Realize that I'm going the other way, but there have been times when I was ill enough that i didn't change my patch for four or five days. In that amount of time, nothing changed, but that's testosterone. If it were two or three weeks, I'd feel the difference.
I'm sorry that this is happening to you. When you can't rely on your body alone to make the hormones you need to keep your gender's appearance, even a small change can cause emotional dysphoria. Once you start up again, you should get your breasts back. Keep that in your mind and try not to worry. You'll be ok.
Sam1234