36 weeks pregnant and a lot of pressure? TMI?

Lat night my boyfriend and I had about three times and at about 4am this morning I started to leak this fluid and I thought it was pee but when I tried to hold it in until I got to the bathroom it wouldn't stop. So I called my doctor's office and they told me to come in tomorrow to see if I was leaking amniotic fluid but now when I go to the bathroom to pee I feel this painful pressure in my l area and my back starts to hurt. What could this be? Should I go to the ER?