Generally you feel much worse when die off occurs. Of course you can control your level of die off so that symptoms ar bearbable, simply lessen the antifungal. But , your symptoms may become more extreme, you may feel tired, like you need more rest.
Since the symptoms of die off and the symptoms of candida can be identical , you can really only be sure it candida if in fact you have been on the diet and are doing everyhting necessary.
Example, I was bloated for months. Being bloated is a symptom of having candida. But any symptom of candia can also be die off , since both symptoms and die off are caused by a release of toxins by the candida. ( candida release toxins in a burst when they die). I knew that the bloating was die off and not candida because I was dilgent with my diet. So since I knew there was know way I was feeding it anything...it had to be die off. And then one day I woke up and the bloat was gone.
I also find that when I have die off I may feel tired , exhausted actually and worn down. I also have some symptoms. But usually my most bothersome symptoms will start to ease. A clear indication of die off. Some symptoms appear such as being tired but others such as vision problems start to go away.