I definitely know what you mean. This happens to me too. I've never told T or anyone just because I thought it was so weird and disturbing! But I will be washing dishes and see a knife and there come the thoughts, things like that. Sometimes its even just random. Interesting that it could be anxiety related though.
So at least know you aren't alone! I hope they are less often, and eventually go away for you! And I hope seeing the T when you go back to school is helpful!