You want the truth? I'll give you the truth as to what I can tell you...
Don't feel nervous at all, relaxing your arm actually works better than tensing it up when you're worried (as I found out!).
The jab when it goes into your arm doesn't hurt. I couldn't feel mine. It's not the needle that hurts, it's the liquid that goes into you. Common fact!
The HPV Cervical Cancer jabs hurt, but only slightly. There is no needle bigger than another, they're all the same size. So what you felt for your tetanus will be the same for your meningitis jab.
Overall - It will only hurt as much as you believe. It's the same size of needle that your tetanus one was... It's got to be better than a blood test! My ole' Science teacher (very wise) told me that if you wiggle your fingers and toes then it won't hurt because, 1) you're being distracted and 2) there are only so many movement signals that pass through your spinal cord and into your brain so that you will feel less of the jab because the rest of the signal is being taken up by your wiggling fingers and toes! It's like a jacket potato but with a teaspoon of cheese. You'd taste more potato!!!
Good luck and it's okay. It can't be as bad as the HPV vaccines!
btw - The needle is only in your arm for about 2 - 3 seconds... For me it was all fine. Some people overreact a lot because they have a worse pain tolerance.
Enjoy! Tell me how it went! x