Ladybug,
The LP itself was not terrible. The worst part was the numbing agent my doctor used, it caused some tingling in my nerves by my tailbone that was painful. After I was numb, I laid down on my side, and held on to the pillow. I was pretty numb, so I didn't feel much. My opening pressure was actually low, so the test was negative for pseudotumor. My doctor says normal is around 100, and my opening pressure was only 80. After he was done, I laid there for a while, then they sat me up, I got dressed, and they sent me home.
Now, I went straight to bed where I laid flat all day, drank oodles of water and coffee, but I still developed the low-pressure headache associated with LPs. My doctor thinks it was probably inevitable because I started off with lower than normal pressure, but it was the WORST!

After 2 days of not being able to sit or stand upright due to the pain in my head being so bad, I went back to the hospital to have a blood patch, which was quite painful. Hopefully, you won't have to deal with that. The LP itself wasn't painful, and as long as you follow directions and don't have really low pressure like I did, you should be fine.
Good Luck!