Any new medication or new dose can take up to 6 weeks for the side effects to subside and for to start feeling the benefits. Try not to worry unless it's been much longer than this. It can also take a few tries on different medications to get the one that best suits you. I've lost count of how many different anti-ds I've been on but am now on two plus an anti anxiety one and despite going through a recent, very severe crisis am slowly starting to feel better.