Pitocin

Has anyone ever reject the opinion for pitocin? This will be my second delivery. With my first I had an epidural at 6cm (wasn’t in any real pain) but when they said I was too far for IV pain medication I got nervous and just took it. The epidural slowed down my progress a lot. I went in a 3cm regular contractions and dilated to 6cm in 20mins. I’m considering going natural this time but if not can you opt out of getting pitocin? It helped speed things up but it elevated my pain to the point I was vomiting and I really don’t want to do that again.