So, I'm fascinated by the plug. I always thought it would be this noticeable thing. But for me, it really wasn't and it happened over days. It is likely urine you are losing but I you are concerned, I would call your doctor. This is easy to check. Especially since you are having Braxton hicks too. Until you can be seen, drink extra water !Let me know how it goes!
How far along are you? With the pressure you are feeling- you should be calling your doctor. Your water doesn't need to break for you to be in labor- the back pain can also be contractions. It sounds like you are in labor to me, and I'd be calling to go in to labor and delivery to be checked out- as my husband always tells me "what's the worse that can happen? They check you out and send you home- it's better then delivering a baby at home, unprepared." Good luck and let us know how you are.