For me, at three weeks any brew lacks maturity.
I've kept beers for over a year with an ABV as low as 4% so I would just leave it and keep checking a bottle every week until it comes good.
The sad thing about this method is that quite often the brew "comes good" just as you finish drinking the last two bottles! If this happens then move the period out to once a fortnight. :thumb:
This is my experience too, I know it's not specific to IPA mind you. My store of ale has quite a variety, and a lot of bottles, and with few exceptions the beers are really really good at 6 months or more. That's not to say they aren't good after say 2 months but they seem to age really well and get better and better.
IPAs though. I did a Proper Job IPA recently where the hops died completely after 6 weeks! Nothing, nada, nowt left. Couldn't believe the flavour and aroma disappeared almost overnight.
On the other hand I did a clone of Mr President, a DIPA about 90ibu's and its peaking now at about 4 months with no sign of dropping off yet.
I did a clone of dead pony club last year and the last bottle was as satisfying as the first, different, smoother probably, but still really nicely hopped.
If yours isn't right yet try and forget it for three weeks say, and then try one, I bet it'll taste much better, or possibly taste of bugger all! Who knows.