The stool test is unreliable. There is no full proof reliable test. The die off you are experiencing should be proof that you have candida.
Im all for the vegan diet, especially for treating candida, ive done it myself with good results. I think its great if you can keep it up. However, you must also be aware that your body might need nutrients every once in a while that you are not recieving. I know a vegan who is vegan for health reasons and thrived on a raw diet, but still needed some fish every once in a while to satisfy his body screaming for nutrients he wasnt getting.
However, this might very well be the candida and not the vegan diet that is causing these cravings or unbalances you feel inside. I sometimes found it difficult to differentiate. The extreme fatigue and apathy you have im all too familiar with, but that should get better soon. I guess what it all comes down to again is that you should listen to yourself above anyone else, but know that die off is a very unpleasant but normal candida related feeling that you need to get through.