I don't know if this is normal, but zoloft works straight away for me.
As such I only take as needed. A few times a year maybe. When I notice my mood taking a dive, heading towards depression, caused by an out of control negative thinking spiral.
I just pop a zoloft in the morning and a few hours later I feel it start to kick in. By the afternoon, my negative thought loops stop and I feel comfortably numb and even happy.
I just take zoloft for a few days to give my brain a rest from negativity, and this usually snaps me out of depression and brings me back to some sort of normalcy (depression is always below the surface waiting, I can feel it).
I get the sides fast too, lose interest in sex, can't come, feel zombie like. I can't imagine being on all the time, I'd rather have mild depression.