17 Days And Very Little Carbonation

I've had my pale ale conditioning in the basement for exactly 17 days at around 68 degrees. I just poured one tonight and there is very little carbonation. I got about 1/8 of an inch head that disappeared in under a minute. The mouth feel has very little carbonation taste as well. Other then that, it taste fantastic. There is a very minimal amount of yeast sediment in the bottle (maybe 1 millimeter).

So, is it time to re-suspend the yeast by flipping the bottles over?

What do you guys think?

Try inverting the bottles, leave them for another 5 days, or so, then open another bottle and see whether you have carbonation. Is this an APA or EPA? If it's an EPA the light carbonation is appropriate. I like my beers with less carbonation because I can drink more and not feel full.

what did you use to prime?

It's an APA that was primed with 5oz of corn sugar.

When you say invert the bottle do you mean invert them once and then place them back normally for 5 days or leave them inverted for 5 days?