Take a deep breath.
Needlestick injuries almost never result in infection, especially HIV. Risk of HIV transmission is 0.3% when you know the patient is infected. You would be offered prophylactic meds just in case which would take your risk down to practically nothing. Hep B has a bigger risk of transmitting, but you will likely be immune to that from your vaccination. Even if you weren't, you would get immunoglobulin and be fine. So needlestick injuries are really nothing to worry about.
Hurting your back from lifting patients is a real hazard in some nursing jobs. Many facilities address this by having adequate lifting devices. It's a real concern, but not a dire situation.
Attacks from patients who are psychotic, demented, confused or just bucking crapholes are rare but do happen sometimes depending on your specialty. This is another thing that is mitigated by a good facility with adequate staffing and good policies to protect staff.
Nursing is very stressful on the psyche, and this is a widespread problem across many specialties. That's where your significant occupational health hazard is. Prepare yourself by developing good coping skills now. See a therapist when you need one. Practice self care. Learn to manage anxiety. This is our biggest struggle in nursing.