Help - vomiting bug

My 5 month old baby has a vomiting bug (we think). We went to a&e yesterday and they told me to feed little and often so he can try retain some fluids. I’m exhausted and was so worried and I didn’t eat or drink anything yesterday until 7pm and today I’ve barely had anything either. I wasn’t thinking about my supply and calories etc. The fact he’s not really feeding and my diet and fluid intake has been awful, will this reduce my supply? Will it easily increase? They flagged that he is very small and dropped to 0.4th percentile so I need to monitor if over the next month but I’m a bit worried now my supply will dip too🙈