It's very unlikely that Patty Duke's case applies to you. Her sepsis happened because she suffered a ruptured intestine. Such a rupture would flood the interior of the abdomen with the trillions of bacteria that normally live in the gut, resulting in an overwhelming and deadly infection. So she would likely have died no matter how strong or weak her immune system was.
Now remicade suppresses the immune system and potentially increases the risk of infections in a general way, but it does not increase your risk of suffering a catastrophic rupture as Patty Duke did. And, as many of the Crohn's sufferers on this board can tell you, the risk of infection or other complications from remicade is far lower than the risks to your health from uncontrolled Crohn's. That's why it is used for Crohn's in the first place.
Serious diseases require strong medicine. So keep doing what your GI prescribes to control your Crohn's, plus adopt a healthy lifestyle (vaccinations, diet, sleep, exercise, etc.) to minimize the chances of getting any infections that could turn ugly on you. With any luck you will continue to successfully manage your Crohn's for many years to come.