37 wks, bleeding, then stopped?

docseason

Last night my stomach was a little queasy so I had a ham sandwich with mustard and some chicken noodle soup.  I then took maybe an hour later, Tylenol 3 also known as Norco (2 of them) for my horrible hip,back, and leg pain.  About 3 hours later I found myself throwing up in bed out of a dead sleep.  I got up to strip the bed and take it to the laundry room (on the way there) had a HUGE urge to use the bathroom and started throwing up again and TONS of pee came gushing out.  When I wiped I had a little red blood clot mixed with some bright red blood and a lot of pink smear.  DH called L&D and they said that I could have caught the stomach bug again (that I just got rid of last week) or the meds could have caused the nausea or some women throw up before/durning labor.  We could come in and they could give me something for the nausea or wait for the contractions to be more consistent.  For almost an hour I was having them every 8 mins and they were lasting 45 sec-1 min.  They finally stopped and I was able to go to sleep.  I woke up this am and I used the bathroom and when I wiped still had the red/pink smear when I wiped, none in my underwear.  No REAL contractions, a few BH when I am up and about.  When I went to use the bathroom this afternoon there is NO red/pink blood smear at all. 

So I guess my question is...what was the bleeding from?  My mucus plug? And why has it stopped?? I have NEVER experienced any of this before...my DS #1 was induced at 37 weeks b/c I had pre-eclampsia and I have had a perfectly heathly pregnancy this time and I am 37 weeks and 3 days (I think, lol)