I've got diagnosed with Major Depressive Disorder, and my doctor prescribed Sertraline to me, the first two days I started with 25mg and on the third I am on 50mg. Currently I feel nothing, no side effects, no changes, as if I am not even taking the medicine.

What should I watch out for and what should I expect in the upcoming phase of taking the medicine? I've heard people say that after the two week mark, you'll start to feel better, how does that feel like? Is it like one day you wake up feeling happier? More clear headed?