My baby had a severe stomach bug at 5 months and we had to have a night in hospital, she didnt keep anything down for 2 days, at the hospital I was told to stop all milk and give sips of dioralyte every hour and then gradually build up adding some built into the dioralyte. I would call 111 for advice and just keep an eye on her
Never worry your being a dramatic first time mum. It’s your baby and if you feel you need to ring 111 , do it. I hope she gets better soon!
Trust your instincts. If it was me, I think I'd be ringing 111, especially if she isn't keeping liquids down x