Throwing up blood. Advise?

Cerys
I'm 11 weeks far and I've had morning sickness nearly everyday since week 6. This morning I've been throwing up but it's mainly been blood. I've rang my midwife and she said it's common because it could be my stomach lining but ita worrying me. This is my first baby and I'm 17 so everything is new and all scary to me at the moment