I was on 50 mg sertraline for many years and couple of years ago had it upped to 100 mg, it was couple of months before I started to feel the benefit both when I initially started and when it was increased and side effects I got were severe heartburn, producing lots more pee and feeling muzzy headed. The side effects occurred very quickly so you need a couple of months to see if they suit you unless the side effects are too severe in which best to see your GP.