Hi N.-
Oh sweetie, you sound really stressed and in need of a break, first of all. See if you can get a half a day away from the girls for yourself. Even if you can manage to go grocery shopping alone, take a few minutes to breathe.
OK, as far as the other issues with food. I have always been a person who doesnt stress too much over food. By 12 weeks both my children were basically eating what we had for dinner. If, of course, they were able to eat it. I cut down on my salt in the cooking, but at 12 weeks my kids were eating things like tilapia vera cruz and chicken piccata. The other philosophy I have is, these are the meals, when you are old enough to get your own food, you can choose what the menu is. And this is not a drive through window. Meals are served at meal time, snacks at snack time. THAT'S IT! If you dont want to eat, no sweat. But you aren't getting anything a half hour later, and I do not make special food. I try to make sure 3/4 of what we are having to eat is acceptable to my kids. I dont expect them to eat calves liver and brussel sprouts for dinner. However, because of their exposure to food so early and my rules, my son, now 3, eats everything I put in front of him and will try anything at least one time.
I say make a new rule, here is the meal, this is when its served. Have at it, or go hungry for now.
Please remember, NO child in middle class America has ever starved. They will get with the program when they realize there is no choice. If you want to give them some illusion of control, ask whether they would like mac and cheese or cottage cheese with pineapple for breakfast. But, that's it. If they argue that they want chicken and rice, calmly say Im sorry but that isnt on the menu for breakfast today. Mommy's job is to make sure you eat properly. You need a balanced diet, so I will decide the choices from now on and you can choose from them. We need to make sure your little bodies grow properly. Then close the discussion and explain they can choose from the choices you gave, or you will choose for them. Give them 30 seconds to choose and if they are still whining, choose for them and STICK TO IT. consistency is the only way you will tackle this bad habit.
Lastly, just take a breath with the little one and don't give in to walking around the house with her. If she has to get up and walk, she will. Especially if it's to find you in the other room. Either that or she will crawl there.
Best of luck to you, please let me know if you need some support. You are NOT a failure, just a Mom trying to make your way through this crazy world of parenting. We all feel like that sometimes.