If u threw up exclusively could be bc of tht
I would say call 111 this evening for some advice if it’s stopped and you feel ok (999/A&E if it carries on) - because you’re pregnant they might want you to see someone https://www.nhs.uk/conditions/vomiting-blood/
I threw up a lot throughout my entire pregnancy but never blood. That definitely needs to get checked ASAP
There’s a thing called coffee ground vomit which is a sign of internal bleeding - really hoping it isn’t that, but definitely worth getting checked out to be safe!
If you throw up regularly it might be slightly ruptured tissue in your oesophagus maybe? I would get that checked out