Barleywine Carbonation issues

I have brewed a barleywine recently with an OG of 1.100 using US-05 it fermented down to 1.013, so it's at about 11.5% ABV. Unfortunately, I did not expect this beer to ferment so low. I bottled on May 6th, so it's right at 7 weeks in bottles. I have opened 3 total; one at week 5, one at 6, and tonight at week 7, there has been no carbonation to speak of. The beer has a slight "pssh" sound when I open it, but even with the most aggressive pour, only the slightest head appears (I'm talking only a few bubbles that can be attributed to CO2 and not splashing when pouring) and no signs of full carbonation.

I know big beers=more time, but after 7 weeks, shouldn't there be more than this? I'm thinking that the yeast has crapped out, and I may need to open the bottles again and re-dose with champagne yeast or something. The problem is, there is a slight "pssh" upon opening bottles, and I don't want to lose any carbonation that may happen... Any advice? This would be a terrible investment to lose.

It took 3 months for my barleywine (OG=1.110 - FG=1.025) to carbonate correctly. If you are hear a slight hiss when you are opening them you should be okay. Just store them at 70 for another month or two and you'll be good. The high alcohol content stresses the yeast and makes the process slower but with a barleywine it will only get better if you wait.