What is the best time of day to take anti-depressants?

I have moderate depression, and I've had it for about a year now. My doctor prescribed me 10mg lexapro. I read the label and it said that it could cause drowsiness, so I took it right before I went to bed bc I have a 5 mth old baby, and I didn't want to be tired during the day while I took care of her. Well, I have been having mild insomnia every night, but last night I could not sleep at all! It took me like 3 hrs to fall asleep, and then I woke up like 10 times! I barely slept at all and I am not really tired. Could it be the lexapro? Should I start taking it in the morning instead?