Is It Possible To Get Positive Result For Chlamydia While Sexual Partner Being Clean?

I have a special situation. I went to urgent care recently due to severe pains in my lower abdomen, vomiting, nausea and loss of appetite. They did some lab work and sent me on my way. As the day progressed the pain got worse and worse so I went to the ER. While there they did testing as well and also did a CT scan so they could look at my ovaries, appendix and intestines. They came back to say that my Mesentric Lymphaditis was back but a whole lot worse than before so they prescribed me with pain and cramping medications and sent me on my way. I got a call the next day from the clinic and they told me that I tested positive for Chlamydia. I talked to my husband and he went and got tested and came back negative. I have never been unfaithful to my husband so where I would have gotten this from is taking a toll on our marriage. I need answers. And I can t retest because I have already taken the medication the gave to me...