Your doing great hun, at this rate you wont need the epidural. I had a posterior labour too, and it took about 10 hours for contractions to go from 5mins apart to 1 min apart. I spent alot of the time in the bath to help through the contractions, with great support, and massage I went 27hrs with no drugs! In the end I had the epidural as contractions were 1 min apart, lasting 45 seconds and baby was stuck, all efforts to move her head failed so I had emergency c/s. But had I known she would get stuck, I would have done heaps more walking (like you!) and moving around, and even the all fours thing like Trillian suggested. So keep doing what your doing and you will be birthing your beautiful bub in no time. Best of luck sweety