Is she jealous????????????????

Yeah, I think you have a pretty thorough list of things she does here, and jealousy seems like a pretty likely explanation. Try not to let it get to you, though. It seems like you already have been, but you should also try to be nice to her and try to make her feel good about herself. (For example, with the shopping ting, try taking note of her sad look and saying you think she should get it.) Killing her with kindness might spark her resentment even more, but that doesn't mean any sort of revenge is necessary. But still, whenever she makes you feel bad, just shake it off and go do something/be with someone that makes you happy. She'll grow out of it in time.