My first thought after reading about your S/O's reaction is that she is most definitely a
Type A personality. I don't see what difference it makes whether you brought your dirty laundry over a few days ago or today. Sheesh.
There is obviously something else that is bothering her that goes deeper than your dirty trousers and I suggest you and her discuss it ASAP.
If you do not and choose to sweep it under the rug, it is bound to rear it's ugly head in the future and who knows how much bigger it will be then.