I had a hip replacement just about 1 year ago, after being in dreadful pain for about 3 years or more.   Best thing I ever did! I would advise to do all the excercises you are given. My physios gave me instructions on the post op exercises beforehand and told me to practice them before as much as I could manage, which I did and it worked. I was up out of bed and walking the next morning and only in hospital 3 nights in total.
Worst thing - sleeping on your back for 6 weeks, but definitely worth it. Am at hospital again tomorrow for check up, but I have almost forgotten that I had it done.
Hope everything goesd ok for you.