O-K, coming from a hybrid type bike, a road bike is going to feel weird to begin with. You do have short legs for your height- which probably means that you have a long torso- so a small bike will be even harder on you, and, standover may be an issue on a properly-sized bike. Don't worry about standover though- unless you get a biuke with a sloping top-tube, you'll likely be maxed out on standover on a bike that fits you....just learn to deal with that when you get a bigger bike, by standing on the pedals as you dismount from the seat, then leaning the bike to one side as you put one foot to the ground, so your nads can clear the top tube.

Performance-wise, on a too-small bike, you're likely to experience numbness; pain; the bike interfering with various body parts; discomfort; inefficiency joint issues....which brings me to another point- it already sounds like your seat is too low. I don't think I'd lower it any more. Raise the handlebars instead...if possible.

To get an idea of where your seat should be, sit on the bike and position one of the pedals in the 6:00 O'clock position (straight down)- with your foot on that pedal being level, your leg should have just a slight (maybe 15-20*) bend in it. If your seat is so low that your leg has more of a bend, then you will likely not be able to pedal efficiently (especially on hills); will have comfort issue on longish rides...and even risk injury to your knees.