Mother's guilt is the most terrible thing. I am going through the same thing. Olivia is starting childcare on 8th Jan and it is just killing me but like you we need the extra money. Like slyder said you can only do your best and that is exactly what you are doing. It will be hard on you emotional but she will love it and thrive. My girlfriend has put all three of her girls in childcare since they were all 6 weeks old and they are great girls who know exactly who their mum is always have stories of what they did during their day.
You'll do great. Best of luck and let us know how you get on.