Disappointed I took this job

My husband is deployed, and we decided I’d try to go back to work for a little while because A. I need to get out of the house and B. We could use the second income. So I found a job at a children’s urgent care. The hours are perfect really for me for now. My oldest will be in school and my other two at the babysitters house. I would work 4 hours m-f and right now, there’s no room for me to request more hours. The babysitter lives less than 2 minutes from my house. So I would drop the kids off 30 mins before I go in and id pick them up 30 mins after I get off. She charges flat rates for 1/2 day and for full day. She’s so wonderful with the kids that they hate leaving to come home! I provide them lunch, but she feeds them her food anyway (which is fine). I am sad because I had assumed I’d get charged for the 1/2 day rate being that I’m only working four hours a day. I didn’t take into consideration the extra hour in commute. So she’s charging me a full day rate which ends up being me making just enough for me to pay for childcare. I can’t complain because the rates are fair, but I’m just a little disappointed that I took this job now and that she wouldn’t charge me a little extra from the half day rate vs a full day. Now I’m trying to decide if gaining the experience is worth working just for childcare. Because obviously I am not bringing in anything extra 🙁. It just feels kind of crappy.