Poppy,
I was very scared, and posted at least three times about "when did you decide", or "when to pull the trigger", etc..
My hip was only intermittently bad. I would have a month of constant pain (walking, sitting, standing, sleeping), and other times with no pain, despite some serious workouts. But, the periods of "good" were starting to be outweighed by periods of "bad". And, I found that I started to avoid activity during the "good" times just to avoid even the possibility of pain.
But, mostly, I went forward because I was not doing what I wanted to be doing, and that is "whatever I want, whenever I want". Of course I mean that from an activity standpoint.
If the fun is leaving your life, believe me, this surgery is but a very little thing in your life. I'm 8 weeks out this week, and I hiked 4 miles with my kids over hill terrain Sunday and didn't even think that I had an implant in my body the whole time. Felt totally normal. No pain during or - more importantly - after.
It is much less scary than you think it's going to be.