Need insights on my vomiting issue

Ok so we’re not completely sure if I have cyclic vomiting syndrome. But last year around this time, I just started vomiting intermittently every other day. It didn’t matter what I ate or drank, it would just happen. This went on for months, and I was so weak that I was exempted from the rest of the school year. My doctor though it might’ve been my birth control, so we changed it and it did seem to get kinda better, but I would still randomly vomit every now and then. Now almost a year later, it started again-not as intense, but my appetite is completely messed up and I get nauseous right after I eat anything. Sometimes the thought of food just makes me wanna vomit as well. But my appetite will fixate on one food item and that would be the only thing that sounds good to me for the rest of the day. Does anyone have any insights as to what is going on?? (I went to the doctor, he didn’t have an answer for me and just suggested cyclic vomiting syndrome)