Its most likely normal, as long as its like little specks or dots and not a ton, its because you've irritated your esophogas from the acid. You may even notice some coming from your nose if you blow it, and that could be because of a burst blood vessel. I experienced rough morning sickness for about 8 months of my pregnancy and the more you get sick the more blood you'll tend to see.
Definitely mention it to your doctor, they might be able to prescribe you something to curb the nausea. If you feel nervous about it, or you think its too much blood don't be afraid to call and talk to them about it, they'll be able to settle your fears easy, probably without you having to leave the house(:
Good luck!
The yellow was stomach acid, that could have made your throat raw and irritated it and thats where the blood came from
Talk to your doctor about it
It is normal I have it happen almost every time I throw up