Venipuncture issues

I had finished all my pre-reqs or nursing except for the A&P. It was too full and I couldn't get in. So, I'm currently taking a Phlebotomy course and really enjoying it.

I have a few problems though. The first stick that I did went GREAT! I had immediate flashback and everything went smooth. The 2nd time, I got no flashback. I immediately panicked (sp?). Ever since then, I start trembling when it comes time to stick. It's not because the needle or blood bother me. It's because I'm so afraid of hurting the patient!

Today, the instructor wanted me to regain my confidence, so he had me do a venipuncture on him....went great. I started to tremble, but he had me do deep breathing. Then he had me butterfly his hand. I hit the wall of the vein, but he just had me move it to one side a tiny bit and I got it.

He keeps talking about how we're supposed to feel a "pop" when going into the vein. I have never felt that and am aondering why. There is only one other person in the class that feels this "pop".

I'd also appreciate any advice you can give me. I start my clinicals at an Endocrinologist next week.