The reason isn't related to anything on the actual page itself, You likely used the Carriage, or perhaps hit some sort of physics variable wrong.
Your character model is actually, technically not positioned right, even if everything about what you see looks right, and this affects how your character "puts up their arm and holds a piece of paper in front of its face" - head on over to http://mlbs.slipcor.net/ and download one of the last two versions of their Save game fixer applet.
I think the last version actually has all the features on it, but the 3rd version is the one that specifically helps your issue.
"reset player model" doing this should fix your sheet issue, as well as any other misc issues that you might not be aware of happening related to it.
"Reset horse and waggon" can assist in fixing issues with the horse that may (likely) have caused the character issue in the first place, however, ultimately, you're recommended to not actually drive the cart until a later time, as its known to be quite buggy, still.