Your experience is quite typical of those of us with CFS, now more properly called ME/
CFS, especially internationally. The ME stands
for myalgic encephalomyelitis (NOT encephalitis). However, sometimes we have to use "chronic fatigue syndrome" just to be understood.
There are two subgroups of patients: sudden onset (you), usually after having a virus, and gradual onset (me), but mine also started after a case of two back-to-back viruses.
I would advise you to stay on your Zoloft!