I think my labor is starting...at 31 weeks!

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For the past two days I have had increasingly worse back pain (way worse than my usual), diarrhea and/or regular movements but now its every time I eat. I also have a very upset stomach, off and on leg cramps and tight pains inside my vagina every now and then. Its like this hit me out of no where! I had my difficulties but none like THIS especially so sudden. 

 

My doc apt is on Friday and Id hate to go in now with Friday being so close. Should I be worried or is it normal to get hit with all of this out of no where?