Nope, it's not not working, you may just be fortunate and miss most of the unpleasant effects. Chemo side effects are immensely variable, being fit and healthy may help, but I was 67 when I had A/C so it's not age! I got a few belated side effects, after I had finished A/C so it's not over yet, but no nausea, no fatigue. Never took anti nausea medication (except what was pumped in during treatment) as there was no need. Metallic taste in the mouth for sure, and a lack of appetite immediately after treatment but that was all. I then had 12 weeks of Taxol with more noticeable side effects. I loathed Taxol but still had no nausea or fatigue. So fingers crossed you continue to have minimal side effects. There's no working it out, but it's good when it happens.