Help plz vomiting blood 28 weeks

Cynthia • Wife to an amazing Man😍Mom of two Gorgeous Girls Jesslyn n Xitlali. FINALLY BFP We Pray To GOD for are Little Jr☺️
I have UTI and my doctor gave me some amoxicillin 500 mg and they told me take 1 every 6hrs. 
Last night my stomach was hurting and this morning I couldn't eat ended up throwing up  and right now  I just threw up and im 99.9% sure it had blood 😫 im so scared plz any one had this problem. Or should i rush my myself to the Er!?