Hmmm....as far as peeing goes, try holding belly up (as much as you can being as far along as you are
) while you pee and leaning forward a little bit to try and move baby off of your bladder. That's the only thing I can think for that.
As far as pooping goes, the discomfort you may be feeling with contractions may be heightened because of that. A stopped up colon can actually stall labor, so your body may be ready to labor, just this is postponing things. I'd do an enema before I did castro oil, as an enema is short lived and castro oil diarrhea can last a while. Also, the enema will work more quickly. I know it's gross, but I'd do it if I was as uncomfortable as you seem. Also, than "can" get things moving in labor too.
As far as cervix position, most moms' cervixes don't turn anterior till labor or till effacement happens. Sweeping membranes is also controvertial and if I would have known the risks I wouldn't have done it. With my first, we had a sweep because we were getting later and the threat of hospital induction was weighing heavily. This turned his head to be asynclitic. I'd have occasional braxton hicks a few hours a day once a week, and those got me to 4 cm. After the sweep, I went into "real" labor, and labored 27 hrs, with minute long contractions 3-5 min apart and only got to 6 cm. We ended up with CS. This time around, I don't plan on it no matter what pretty much. But it's your choice.
If you want to efface your cervix, sex is good, prostaglandins (like primrose oil) taken vaginally or orally can help too. When you feel a ctx. go into a labor squat to help baby head move further down (I know he/she is already low) and to bring cervix forward.
That's pretty much all I can think of, I hope other's have more insight. Oh, and also, I wouldn't count dialation as a sign of your body being ready for labor, I was 4 cm at 38/39 weeks and didn't go into labor till after a sweep at 41+3. But I would do everything to clear the way for baby to come out as soon as possible, as you do seem to be in a lot of discomfort. Hang in there though! Much Love to You!!!