28weeks pregnant leaking more fluid from my lady part.?

before it was a little bit white sticky stuff. I was laying on the lounge this afternoon and sat up and all this watery fluid stuff came out and it ran to the back of my undies making them yet enough to change them and i had my partner take a look and he could see it coming out of me. It was like watery with a white like substance. We have not made love for 3days. Unsure of what it was. Has any one have any ideas as to what it was.