Pooks - you will definitely get over it, do not doubt that. Naturally though, getting from the point where we experience fear from an experience to the point where we are comfortable (maybe even enjoy it) takes time - and some difficulty too.

I think if you ride those hills more and more - going up in little increments (say, today you ride them at 10mph - then next week maybe 12mph) - you'll get used to it.

Going downhill fast is practically an art in of itself. On the one hand, the feeling of speed and ease of pedaling is nice, but then it can also make you feel out of control. I know there is some intangible speed or number in my head for any given descent where I cross the line from fun to OMG! The more you do it, the higher than number goes.