Dilating?

Any of you moms who have been pregnant before every checked your own cervix? I have been having this weird cramping/tightening/pain since last Thursday and my gut has been telling me that it's not just Braxton hicks. I used to check my cervix when TTC so I know what it used to feel like. I checked today and it was very very soft and open, about the width of my finger, which technically would be like 1.5-2 cm???? Freaking me out because I'm only 28 weeks. I haven't had any bleeding or anything that looks like my mucous plug or my water breaking which is a plus. My next f/u is in 2 days, but my OB office usually doesn't start checking you until 32 weeks. I don't know if I should be concerned, or to just stop looking stupid do up on the internet! Also, my mom was 50% effaced and 3cm dilated at 26 weeks with my sister who was born premature. I'm not sure if premature labor can run in the family?