I'm not really into "physical nursing" as you put it either. I like knowing stuff, and I like seeing people do stuff. By that I mean, I love learning about physiology and pathophysiology, and I enjoy seeing other people enact various medical interventions (most of which are things nurses don't do). However, I'm not really keen on actually doing anything hands on. I'm not squeamish, and I'm not scared of needles. It's just not what I want to personally be doing. I got into this for outpatient psych as well, lol. The only thing I'm averse to is feces. Yes, when I started it wasn't that big of a deal, but now I'm rather repulsed by it to the point I have to calm myself when exposed to it. Yes, I'm being serious. I'm not visibly upset by it, but I have a mental crisis of "If I see this **** one more time I'm gonna flip out!" I'm actually leaving hospital nursing entirely in August (or sooner) so that'll be a welcome chapter closing in my life, lol. I don't want to get used to it either as the site and smell of human excrement shouldn't be a cool, normal thing.
The best way to get over needles would be to go to the pharmacy, buy a bag of diabetic syrines, and randomly jab yourself with them, lol. Just kidding. Don't do that. I have a dark sense of humor, lol. Remember you're going to be sticking other people. Not yourself.
As for getting in better physical shape...absolutely!! It's great to be in shape. If you're not now and don't exercise you have to will yourself through the first couple (or more) weeks of it, but you get to a point where your body doesn't feel sick and tired. At that point, you merely exercise, catch your breath, shower, and go on about your day. Once you do it enough and habitualize it then it's part of life like eating dinner. I enjoy working out. There are a variety of positive health benefits that I'm sure you're already aware of. Right now I look forward to it because it's when I get to loosen up. I abhor stretching for the sake of stretching, lol. Seriously, as much as I work out I haven't been able to reach down and touch my toes for the better part of a decade. Tight hamstrings. Anyway, I carry my stress in my neck and back muscles. Other than the poo I mentioned above there isn't really anything that noticeably bugs me mentally. After a run, a good lift, etc. they're loosened and lubricated. I can then stretch out the stiffness which I really look forward to. Remember to hydrate and get plenty of sleep.