Hopefully it's nothing serious

So today is Wednesday and Vegas and I haven't gotten out and had time to do anything this week yet except rough house, tug, and zoomies. Tonight she was her usual bouncy self although she got sassy with the boys when she thought they were fighting. She played with her toys and sassed me. Then, around 6, we noticed she had started favoring her right front. After manipulating, palpating, and feeling for heat, I wasn't able to find anything. She didn't show any indication of distress but as the night wore on, she put less and less weight on it. I'm starting to get worried. We have an AKC trial this upcoming weekend, too, and I would hate for us to miss out on it. I hope it's nothing serious and maybe she just stepped wrong and stunned a nerve. Here's praying for 'all better' tomorrow!