When we read words here rather than hear it in person, sometimes it can be hard to tell the actual meaning-
The person at your doc's office may have only meant that, since you have had so many setbacks in the past year, your body is tired of fighting the infections....
not that 'this is the end for you'. Just that your body is tired. That happens to me too. Its kinda common sense really.
Also, since she is only a coordinator and not a doc or nurse or tech, I wouldn't put much weight on what she says. Don't worry-you'll bounce back with some time and alot of work. Look at the year you've had-thats ALOT.