my new bike?

[Miranda]

Fwiw... Just at a glance, I personally think your saddle is a bit too high...

If your saddle is too high, you will have pelvis rocking back and forth while pedaling and likewise rocking pressure on your pubic bone soft tissue parts. Also, if you are rocking as you pedal, it makes it difficult to feel solid and keep your balance.

I'm long torso, short legs, just about like yours, and just did a stand over of my bikes. Bare foot, the top tube is just touching the soft tissue of the pubic bone. With shoes, I have a little clearance.

OK, here's what makes the difference in what I see in your saddle height, vs. mine...

If your pants are low cut and the waist band lays across your boney bump of your hip bone crest... that is where about the top of your saddle should be level for height. When I stand next to my bike, I can press the nose of the saddle right into my hip bone bump- about equal height.

Another check is as you are seated on the bike, and put your heel (with shoes you ride in) on the center of the pedal, your knee should be about locked out at the bottom of the stroke. When you move your foot forward, and put the ball of your foot on the pedal as you would to ride, you should have a slight bend, roughly 15-20degrees. OK, do not instinctively jam your heel down when the ball of your foot is on the pedal and think "I'm still knee locked out" because you do not actually pedal that way- usually your heel is slightly up (gives that bend) in motion.

Your knee position forward or backward (saddle fore or aft) should line up (with the saddle height set first) like a straight line from front of knee passing thru ball of foot, when pedals are at 9 & 3 o'clock.

Your top tube is naturally going to be shorter with a smaller frame, but you have alot options in terms of stem and bars to get comfy. If your old bike is comfy, take it in with the new bike and show the shop this is what makes my body happy. See what can be done with that.

Also, on balance, are the new bike tires skinnier width? Was the old bike smaller tires like a mtb? Or standard road bike 700c tires? You can switch tire width (up to a point) if this helps you get used to your new ride.

And yes, usually lighter, more performance oriented bikes, are more "twitchy" as they say. However, if the bike fits you, this should pass.

You and your machine should become one- the whole ride just disappearing underneath you. That is a piece of what cycling heaven is made of. Take that from someone who has had both cycling hell in a bike sold to me two frame sizes too big, to what I own now- heaven, fits like a glove.

Good Luck!

EDIT ADD: For the $ paid at the LBS, they should make it right. That is part of the point of what you pay for in the lbs price (that's a reputable shop, anyway).