Braxton hicks that take your breath away, and pelvic pressure?

I'm a nurse so I'm on my feet all day and my job is pretty demanding. But I was in nursing school when I was pregnant with my first and didn't experience this until like 35-36 weeks. I'm 30 weeks now. I've had BH all day and quite a few that have taken my breath away or made me stop what I'm doing and wait for it to be over. I've also had a lot of pelvic pressure and pain. I know this might be absolutely normal for third trimester but at what point do you get concerned? I know if the contractions get closer but that's about it