Is my waters leaking? Am I peeing? Is it discharge?

So I'm 27 weeks pregnant. Had a lot of increased discharge for me entire pregnancy. Right now I'm having this weird sensation down there. You know the feeling when your on your period and you can feel a big blob of blood leave your vagina ... That's how it feels but constant and nothing leaves, there's nothing in my panties like blood/discharge/water and iv wiped and nothing ... Feels like it's just sitting there at the entrance of my vagina waiting to come out! Iv tried feeling around for something but nothing! What could it be?