If you have blood poisoning will you surely die after getting worse for 4 days?

No: Septic shock usually resolves in 24-48 hours, but may persist for a longer period if the infection is not under control, an abcess is lurking, or the heart and lungs were injured in the initial collapse. Talk to your ICU doctor and see what they are doing to turn around the septic shock, or if the illness is simply a recovery from severe injury (lung, heart, kidney, liver, etc).