When is it malpractice?

I had major surgery on the 20th, was sent home on the 21st, by the 23rd i knew something wasn't right (because of the pain i was in), on the 25th I was in the emergency room which warranted a $75 co-pay. the doctor that i saw in the emergency room not only told me that he helped in my surgery (never seen him in my life) but he told me my white blood count was at 18000 (11000 is normal) which indicated that i had an infection, he gave me narcotics for pain and sent me home, on the 27th i was back in the clinic of my doctor who did the surgery, I had a thorough exam (which I didn't get in the emergency room) my blood count was even higher, she immediately sent me back to the hospital for a CT scan and dicoverd that i did in fact have an infection, i was immediatley admitted, stayed for 6 days and had to have surgery again. My feeling is i shouldn't have to pay the co-pay and the doctor that i seen (he's my doctors partner) should be reprimanded for lack of care, had he did what he gets paid to do i would have been admitted the day i went to the emergency room instead having to endure more4 pain and suffering. I have exceptional medical coverage thru my job.