Sleep Training... HELP!

Erin
We have been trying sleep training for 2 weeks, she turned 5 months last Friday. And it's NOT working. She gets herself to sleep great because of the sleep training, we did the "fading" technique and that works for her initially getting herself to sleep at night. But she is still up every 3 hours to eat. And she's HUNGRY... she will scream and choke if I don't grab her. She has never taken a pacifier so that doesn't help. We have started to give her oatmeal even though I didn't want to, during the day to maybe fill her up and it's not working. She takes 4oz bottles (never more and we have tried everything) and eats about 28-30oz during the day which should be enough. Help?? Advice?? Naps are great, we did cio for that and it's totally helped, but nights... NOPE! Is my baby just a fatty and I will never sleep again??