My Sexual Partner Just Informed Me The She Tested Positive

My sexual partner just informed me the she tested positive for trichomoniasis. I was last tested in may 2015 but just for chlamydia & gonnereha, which came back negative on both. She thinks that I have been unfaithful which I haven't. Is it possible I had trichomoniasis all this time and it didn't show on my last test because they didn't test for it? Or would it have still shown up regardless if i had it. I'm not sure, something doesn't add up