Anxiety and Depression

I’ve had bad anxiety my whole life and it runs in my family. Two months ago for the first time I started taking medication for it which I can’t tell a difference in myself since I’ve started taking it although some people see some of a difference. At first I was taking it at night and it worked best then I tried taking it in the morning to see if there was a difference. After that I became depressed/sad and had no energy. I told the doctor and she changed it to a higher dose of the same medicine. I started taking it at night again and it was good again. I felt sick for another reason the other night and ever since then I feel depressed again. I don’t know why.