What Causes Fatigue Along With Vomiting Post Knee Replacement Surgery?

I went in for a total knee replacement nov6 after surgery I was very sick they had to give me 3 pints of blood and on the 5 day my dr sent me home and I was still throwing up, came home and for 3 day still throwing up around the clock I fainted and went by ambulance to the hospital a different one and I had a bowel obstruction. can you have problem after receiving blood. I have 4 autoimmune disease and it worries me I don t feel the same and my knee Dr wont help me my leg is very hot and still in sever pain I need help I have lupus, vasculities, hsv, rhnodes, fibromyalgia ostoarthritis please can you help please