You are definitely NOT alone! I do the same thing at the grocery.....even after taking a meticulous inventory of what I already have and making a detailed list of what I need.

I get to the store and the cloudiness takes over. Maybe it's the noise, the lights, the crowds. Who knows. But I can walk up and down aisle after aisle and not know what the heck I need. Even with a list! This is why it takes me so long at the store.

I can make a list and send DS to the store and he comes home with everything on the list (and then some) but it's so much easier for me because my mind isn't bombarded with multiple items.

I guess this is the "brain damaged" part of MS. I don't like it. But I'm thankful I'm at least able to recognize that it's happening.