Fasting on Vyvanse

I’ve been on 30mg for a solid two months now. My start time for work is at 6:30am till 3pm. But I’ve notice I cannot eat breakfast. I’ve tried different tips from here and food in general makes me nausea in the morning. I even threw up at work after I drank a protein shake. Since then I just fast till my lunch time which is at 11am. Anyone here fast past breakfast and just eat lunch and dinner? Is that a good thing or bad thing to do? Any recommendations on what else I should do or try out?