I agree the shoulders are extended enough, and I love the roping. I don't think that's your problem. The collar and lapel spread quite wide which narrows the appearance of the shoulder a touch, but again I rather like the style. When I look at it, what draws me is that the quarters look very open, tapering away a bit too much, and also perhaps the skirts are just an inch or less too long. The overall effect is to make a triangle of trousers that's more prominent than your triangle of shirt, and therefore makes you look bottom-heavy.
There's probably not much you can do about the cut of the quarters now, but I think three things might make you feel better about this pic next time you take it: first, take the jacket up just a tiny bit higher. Second, don't wear patterned trousers with this one as you want to diminish the bottom half of the picture rather than accentuate it. And third, I'm not sure what camera you have, but I know my little pocket one really exaggerates perspective. So try taking the picture from a slightly higher vantage point, somewhere between the chest and the navel: I think this angle is too low, and also making you look bottom-heavy.
But you know what? My first impression was "nice jacket", so sometimes maybe we just over-analyse...and I'd be interested to see what the more knowledgeable tailoring gurus have to say.