Good thoughts above regarding high level of carb. Just another possibility - remember that carbonation is a function of the ratio of priming sugar to the volume of beer. If you used the full amount of priming sugar but did not bottle the full recipe volume (didn't top off enough, left too much behind when racking to the bottling bucket, etc.) . . .you will carb to a higher pressure.
As far as the taste - as McGarnigle & Revy point out, 2 weeks is too early to judge. Give it a couple weeks. Blueberry witbier sounds kinda good, hope it turns out.
make beer not war