Hello.
I hope you are not depressed. Depression can lead to such symptoms as loss of libido (and hence, the sexual effects), fatigue, loss of interest and motivation, weight loss or gain, sleep disturbances, etc. I am not denying the effects of surgery, but it could be an additional cause.
Fatigue is not a usual side effect of the surgery on cervical spine. Make sure the fatigue is not weakness.
Regards