Hey. I'm Currently 21 Weeks Pregnant And Rhesus Negative Blood

Hey. I'm currently 21 weeks pregnant and rhesus negative blood type. I had a severe nose bleed last night and this morning which id say was equal to about half a mug of blood each time. Should I see a doctor? As I've heard that any loss of blood during pregnancy and being rhesus negative that I have to have the injection for it? Thank you