Head disappears quickly and no carbonation

[Steveruch]

I recently brewed a no-boil batch of stout where I cold steeped the dark grains. I left them out at room temperature instead of in the fridge and accidentally did a mini sour mash.
The slight sourness is not bad; kind of makes it a bit of a Guinness clone. The problem is that the head disappears instantly and there is almost no carbonation.
Why?

 

[tsholl]

What was your OG and FG? Did you add sugar right before bottling? Or are you kegging?

 

[Steveruch]

What was your OG and FG? Did you add sugar right before bottling? Or are you kegging?

1.050 and 1.017.
I added sugar. Most of it went into a Tap-a-draft and some went into bottles. I also added a couple of prime tabs to the bottles. The beer acts the same from both.