Exhausted

I graduated in August and got my license in October. I started working in November at a community health clinic. I travel between 4 different offices, and care for everything from your standard insured patient to homeless people who live in the woods, depending on which clinic I'm at. I love my job. LOVE it. My coworkers are great, very helpful, and easy to get along with for the most part. The work I do is extremely rewarding...the kind of thing I would do for free if I were able. I work 7 1/2 hrs, w/ a 30 min paid drive between offices and an hour for lunch. I travel right before lunch about 4 days a week. I work M-F, 8:30 to 5:30 w/ about an hour drive (due to dropping my children off).

I am EXHAUSTED. I feel so drained when I leave at night, like I have been run over by a truck. Where I used to be able to stay up until 11, I find myself dozing off before my kids are even in bed (so before 8:30). Other people I work with have mentioned feeling the same...

Is there anything I can do??? I cant drink coffee as it makes me violently ill (serious GI upset the second I eat anything afterwards). Mt dew doesnt do anything for me anymore. I am sleeping early. I do have a 2 and 4 yr old at home that climb into my bed in the middle of the night which isnt helping I'm sure. I'm just so exhausted.