Hi Siun I haven't personally been diagnosed with Janumet, but I've done some quick google search on it. According to WebMD, some common side effects might include nausea, vomiting, stomach upset, diarrhea, headache, weakness, or a metallic taste in the mouth.
Remember, though, everyone's experience can vary, so it's always best to chat with your healthcare provider if you have any concerns or questions about medication side effects.