Concerned about B. smithi behavior

I'm hoping this behavior is just a sign of an impending molt but I've never seen it before so I'm a bit worried. My adult smithi has been in my care for two years and has not once refused food until two months ago. She is slower than normal and has rubbed some hair off her behind since last night. None of this would concern me except when she walks she drags her abdomen instead of carrying it off the substrate like normal. I only noticed because there is a little indentation behind where she walks. I took a picture but I'm not sure if it comes across well enough.

Is this just another possible sign of a molt? Or should I be concerned? I've been caring for ts for a few years now but only my little one have molted for me as of yet. Any advice or experience would be greatly appreciated.

One other thing. The grey fuzz on her rear, could that be a fungus? It wasn't there yesterday. I keep her on dry substrate with a water bowl. I live in Utah and it's pretty dry as far as humidity goes, I think today it was 13%. I do have my tarantulas in a cabinet with glass doors but don't have any mold issues. I'm hoping it's just from her kicking or laying down her hairs in the substrate.

Here's a better picture of the fuzz on her rear.

The darkening of the abdomen indicates an upcoming molt. A smithi this size can pre-molt for months

The gray stuff looks like urticating hairs

It looks like loose urticating hairs.

Those are just loose urticating hair that had some dirt caught up in them. My B.klaasi has that on her butt every time she prepares to molt lol

Thank you for the replies! I'm more worried about her dragging her abdomen when she walks, I don't know if it's because she's going to molt soon and is just having trouble moving or what. There is a little trail like if you drag a stick in the sand that is following her around her container. Like when you pull a sled through the snow it leaves a path, that's the best way I can describe it.

I agree with the others. Since you know that she is preparing to molt, you can easily (and almost certainly correctly) attribute any odd behavior to the effect of that often protracted process. Remember...the simplest explanation is usually the correct one.

Well, she molted finally! I'm glad that the dragging was not caused by something else. I'm excited to pull that molt out of the tank since it's my first adult molt in the years I've been keeping. Now I can get some practice sexing from a molt if she didn't munch on it lol. More importantly I hope she is still a she since sometimes they switch it up on you when you think you're sure lol!