Bo1234, you seem very anxious and really need to talk to a doctor about that. Being 'stuck' by a needle is different than using the plunger to inject yourself. That's the difference. Air inactivates the virus so a needle stuck into you would not expose you to HIV. Injecting yourself is different. And that did NOT Happen to you.
Medical accidents could occur. If infected blood is contained on a syringe and then injected by accident in someone's veins, there can be infection. But as you can imagine, this is not the same as getting prickled by a needle left under environmental influence.
The ways HIV is spread have already been exposed to you previously. There is also a really nice FAQ posted by Curfew on the top of this page.
All the best.