My experience is, probiotics can do wierd things to the immune system. They can also be very helpful. If I were you, I would try another brand or try one with a higher/lower amount of bacteria. Or try one with mixed bacteria.
Having Candida can make you feel tired. Probiotics are the "good" bacteria. I have also felt extra tired when starting on probiotics because my body is fighting off the Candida. I try to remember to use a probiotic on a regular basis.