How do I get MY sleep schedule straight?!

So my daughter turned 4 months about a week ago. I feel very lucky because she's been sleeping through the night (9ish pm to 5ish am- then eats and goes back to sleep until about 8 am) since 3 months.

The issue is with me. I can not, for the life of me, sleep at night. It's 5am right now and I'm still awake. I have tried everything and I can't sleep. I know she's going to wake up soon and I'm going to be misriable all day. It's making me so unproductive.

I went to my doctor about it and all she said was to quit drinking caffeine and start exercising. She doesn't have kids-- I don't think she gets it. When I'm this exhausted if I don't have caffiene I seriously cannot function. My husband works 60+ hours a week and I don't really have time to go work out. In all honestly, I'm so tired I don't think I could work out even if I had time.

I really had hoped she would prescribe me something to help me sleep, but she wouldn't. I didn't want to take anything strong like ambian (since I do need to wake up for the baby) but I need something. Anything!!!!

Any advice???