Small pain.... wwyd? (Long)

phishgirl29

So last Monday, when I went into my 17 week appointment, I mentioned to the doctor (not my regular OB) that I've been feeling a small pain in what feels like my cervix on and off for two days prior, about 3 episodes or so every 5 minutes, but not lasting more than 30 minutes at a time at least 4 times a day.  I was super active last weekend walking all around Manhattan so she said it was probably over activity, baby kicking my cervix, or nothing at all.  She did NOT check my cervix, but the baby's heartbeat was 145 ad my blood pressure was normal.  It went away or the most part during the week but not entirely. 

Yestererday I went to the gym (I've been going all throughout this pregnancy) and did my usual walk uphill for an hour and light weight program.  The pain has started up again, but now it's more consistent and hasn't gone away as quickly as before.  I called the on-call doctor who told me to rest all day today, don't get up unless I have to, and drink plenty of water.  I'm also supposed to call tomorrow and see if I could get in tomorrow to have them check my cervix.  I'm so worried now.  Everything I read says preterm labor or incompetent cervix, and they really don't do much for it unless you are 20 weeks +.  Am I crazy?  Has this happened to anybody else?  I've had no bleeding or non-clear discharge at all.  I'm just so nervous!