The whole process is really scary but If it is something you are committed too it is worth it. I'm 7 and half months out and have lost 10 stone. The nurses and doctors will put you at ease. They only put the cannula in once you get to theatre and if you let them know you don't like needles they will make sure it is nice and easy for you. As for a catheter, very rare, I had one once for something different, not weight loss surgery related, and it didn't hurt. Just a bit uncomfortable. I was awake when they did it, if you had to have one - and like I say very rare, then you would be asleep. Talk to your provider about your concerns and I'm sure they will be very supportive. Best of luck, if your are ready for all the other stuff related to weight loss surgery, you can get through the hospital bit I'm sure. Best of luck x