So normally I work 8 hours today and get an hour break which is great, today I only worked 10.30-4.00 and my boss wouldn’t let me have a break when I asked for one. I was super hungry and felt sick from it but she just said I wasn’t entitled to one and we got into a disagreement. Normally I have no problems being able to have snacks but I was on a training day at work and couldn’t get out to eat anything today! Do I have some sort of rights if I’m feeling sick from being hungry? I only needed a quick 10 mins to eat something. I am 20 weeks pregnant

EDIT: I’m in the UK so not sure if laws are different?