People in the know know that there's just no substitute for a road bike for riding distances like that. It could be that you overdid it a little to start, but eventually, if you keep wanting to ride, you will benefit from a road bike that can be fitted conservatively, like a touring bike. A road bike doesn't necessarily have to be an all-out road racing bike, contrary to popular gonzo newbie road bike owner opinion around here. But by the same token, also contrary to popular opinion, an upright position is usually harder on the back, not easier.
I myself used to subscribe to and recommend the Rivendell philosophy on bike fitting, but they have gotten a little extreme in their views, so I can't really use them as an example anymore. I mean, I would never, ever recommend riding with the handlebars higher than the handlebars if you can avoid it (Ok for riding around the neighborhood, but not for any serious distance), but, on the other hand, for pleasant, serious but recreational riding, like touring, you want a road bike that will allow you enough adjustment room to have your drop bars anywhere you might want them from level with the saddle to an inch or two below. On such a bike, the drop bars aren't there for speed, but rather for the hand positions (and hand positions are also body positions, so this matters a lot).
If you end up looking for such a bike, there are some on the market, and they are generally the road bikes that have a triple setup just like your hybrid does. They aren't ideal in the sense that they can't take fenders or tires much wider than 25 mm, but they will do the job if you don't need those characteristics. Then there's always the real, full-blown touring bikes.
I have no idea what your bike shop can do for you, but one thing you could do first is to try adjusting your existing hybrid to be a bit more like a road bike position. If you put bar ends on the flat bar, you can have a decent hand position. Put the bars level with the saddle or a little lower, make sure the saddle is in a good position (high enough, neutral fore-and-aft). Then try the same rides with that setup and see if you like it better. You might even find that it suits you and that's road-bike like enough for you like that.
I think that some of today's more performance-oriented hybrids are the true descendents of the classic 1960-70's 10 speeds like the Peugeots, Schwinns, Raleighs and so many other makes that everyone rode in those days... as long as they haven't been ruined by having plastic carbon parts on them, and they don't have front suspension. All they are missing is the drop handlebar, but that can be fixed easily enough (assuming you won't be needing an unusually short stem in order to get the bars close enough to you where they need to be).
Good luck. I'm sure it wouldn't hurt to talk to your bike shop though. You never know, they might be able to offer you some kind of deal.