Advice please! TMI

So I have been having some vaginal pain that increasingly gets worse, goes away and will come back and do the same thing. Well yesterday I had some dark red spotting and I've also felt some tightening in my stomach followed by some cramps. I just want to know if anyone has experienced this and what is was or what I should do. This has been happening for the past 2 days and I'm currently 26 weeks 2 days.