I'm in my second semester of nursing school and so far we have not had clinical in the OR. I've been on med surg, post-op, wound care, and rehab.. You may get a clinical instructor who will pull students to go see new things, like things in the OR. A lot of times my clinical instructor will pull whoever she can find for opportunities like getting to see surgeries. I have one friend that cannot stand blood and my instructor has made it a point to pull her the next time an opportunity arises to get her over her phobia. It all depends on your instructor. The doctors and nurses in the OR are amazing with student nurses though. The ones at our hospital told us if we're feeling sick or whoozy to sit in a chair or don't say anything and just walk out. Better to leave then drop to the floor and bust your head.
I totally understand the needles/IV's. I can't stand needles myself and we learned to give shots by practicing on each other and ourselves the first week of "boot camp". Not to sound rude, but you'll get over it. You'll realize it's not the needle that hurts as much as it is what's in the syringe. Eventually you won't think twice about the needle. You will probably have to take out IV's during clinical though. Most of what I do in clinical is giving meds, doing assessments, giving shots, and taking out IVs. They should prep you in lab for actually performing these tasks before clinical comes around so you're ready. Honestly, you'll get to where you're so in the moment when doing these things that it eventually won't bother you. Once you do it once, it'll be like it's nothing.
I was right in your shoes in August. I almost made myself throw up at the thought of doing anything with needles or IVs. Your instructors are there to help you and encourage you, not put you down. If it wasn't for their encouragement I could've never stuck myself with a needle.
Don't let it discourage you!! Good luck!