Mel - three sucks doesn't it?
It will pass. My DD did exactly what you are describing and I did exactly what you are describing...and she's OK. I find the 1/2 year mark to be the most challenging. I am a preventer rather than a curer so picked stuff I knew she would eat. I often found that growth spurts made them really tired at night and less likely to eat much other than a sandwich so sometimes when I feel it coming I give them their main meal in the day time and something lunchy for dinner that's easy to eat. I'm not really a strict parenting routine type so this works for me and my little free spirits
SOme things that helped us were occasionally picking fun stuff to eat (homemade pizzas, fajitas, homemade hamburgers - scaled down for the wee one) that she could help construct her own often made her forget about the whole "I can't" thing. As does lots of encouragement. Heck she still pulls it out of the bag.
Bedtimes well we have night terrors here so I'm still often in three different beds every night. I did start to stress when DS was really little and demanding too so I totally understand that worry. I also find that the keeping them calm and not building up a battle works much better.
I found that comparing the kids (ie look DS is doing that..) did not go down well and only made the situation worse.

Wow that was a disjointed ramble but just wanted to offer some support