Friend came to stay with me. Known each other a long time. She tried on a belt at my house because I suggested it would help with her new jeans that she felt she bought in too big a size. It looked great. She said it was a really nice belt where did I get it etc.
I've had it years but it's the one I wear whenever I need a belt so didn't offer her it.
Haven't been able to find it. Asked her today if she remembers where I put it and she says yeah it's in her house and that she accidently took it because it stayed on her jeans 
She then tells me she put it away in her cupboard when unpacking so out of sight and that's why she forgot to mention it.
Aibu to feel really weird and uneasy about that? I just don't see this happening for me and me not mentioning it as soon as I realised. Plus she was wearing her jeans the day she left my place 
Aibu even thinking the worst. Its not the belt BTW. Its totally the principal.