I'm seriously freaking out a bit!

So... I'm getting more and more stressed by the day but my contractions seem to be slowing. I'm super happy about that but now I'm starting to think I'm going to be pregnant forever. The thought of being 40 weeks pregnant is scaring the hell out of me. My oldest was born at 39 weeks 3 days after 27 hours of labor because she was sunny side up. I was in so much pain from contractions right on top of each other AND back labor that if that happens again, I don't think I could go natural. Especially being exhausted like I was at 39 weeks. At 39 weeks, sleeping was just not happening. I literally got an hour a night! Being that pregnant and uncomfortable is scaring the hell out of me! I want a natural birth but at 39 or 40 weeks I feel I will be too dang tired to go natural. I KNOW the chances of me getting that far are VERY slim but I worry about everything under the sun and my mind is just racing with these thoughts. I seriously think my mind needs to just stop and take a break, take a breather and stop. But it won't listen to me!