How long?

My doctor put me on 75mg twice a day to start me out on this medication. I've been on it two weeks. How long before you feel the positive effects if there are going to be any with me? I have lost a couple pounds, I feel a bit tired because I have not slept well most night but I understand this is common and should resolve in a while but other than that, I don't feel any impacts other than the tiredness and a mild headache most days. I have adjusted my dose to the first dose at about 6AM and the 2nd dose 6 hours later around 1PM - hoping to avoid the sleep issues.