jules i used to be needle phobic too. BELIEVE ME you can get over it :S :S :S
when i was a kid i had to go for hypnosis to help deal with it, because my dentist didn't want to see me again without something being done.
the 'hypnosis' involved sitting comfortably, eyes closed, breathing deeply, and concentrating on total relaxation, muscle by muscle, descending from the top of my head to my toes.
the doctor would then ask questions, describing a scenario that gradually led up to a needle encounter. such as, "your mother just told you that she is going to book an appointment with the dentist for two months from now. how do you feel? and i would let him know if it was good or bad by lifting a finger on one or the other hand.
whenever i felt bad, he would switch off the needle track and go to the happy place. he had asked me what was the best place in the world where i felt the most comfortable, relaxed, and happy, and i had said a particular beach.
so any time i started to feel stressed about the scenario, we would go to the beach. and then he would back up a few steps and start again with the scenario.
i remember being 8, back in that dentist's chair, doing all my breathing and relaxing, when the technician came in with the mask and gassed me with nitrous. they weren't going to put up with any more crap from me i guess

in my 20s i had to try to deep breathe for needles, but i was likely to break down in tears of relief when it was over.
at some point i decided enough was enough with the fears!
i did things like flying and skydiving to get over my issues with heights.
i joined a public speaking group, and took singing lessons and performed in recitals to get over stage fright.
and apparently ms came along to help deal with my needle phobia. the spinal puncture was brutal for one thing, and i had to ask for more numbing in mid-process, because when he started i could feel the needle going into my spine (not hurting, i could just feel movement and pressure and that was too much information thank you very much!) anyway now i'm pretty okay with needles and although i still can't watch while they take blood, and it's by no means fun or anything, i'm so interested in finding out my bloodwork results that i want those rotten pinpricks.
i have to admit that a significant chunk of my decision not to take the usual ms drugs had at least a bit to do with the idea of self injecting for the rest of my life!
future meds or no, in the short term there will likely be a number of tests involving needles while they help you work out the answer to your current problems. maybe it won't even go as far as the lumbar puncture. you've had your 2 young ones - did you have the epidural? i don't imagine it would be much different than that.
at the end of the day, your answer might be something totally other than ms, but while they're figuring it out - where is your happy place?
you may want to inquire if a lumbar puncture is in your near future. if so, there has been some recent discussion on that procedure - see the "where do you begin?" thread by craftiegal
http://www.thisisms.com/ftopicp-50518.html#50518