Any ideas?

Lakken • Pregnant with baby #1
Friday I was taking antibiotics and the taste made me sick and I started throwing up. And after I threw up all my food straight blood started to come! I went to the er and my blood work came back normal and the doctor said it could have been a blood vessel bust from throwing up or and stomach ulcer bleeding I was 26 weeks and 1 day when it happen! I don't want the stomach ulcer to do it again if that's what it was any ideas?