Hey ladies, so I'm 36w 4d pregnant. Starting last night, I began feeling an intense pressure in my lower abdomen, along with some moderate cramping/tightening of my abdominal muscles/ligaments. It eventually subsided and all went back to "normal" (we're pregnant so whatever that normal is anymore?) While at work today, it started again out of nowhere, completely off-guard, and this time, the tightening was even more intense and almost painful. It was alarming enough that I felt the need to call my doctor. He said he thought they were just Braxton hicks contractions and just to monitor them, and that the baby is probably just descending into the birth canal. He also mentioned that if I did actually go into labor now that I'm far enough along that they wouldn't stop it (yikes! So scary to think about!)  Now, over 6 hours later, I'm irregularly getting the same contractions and feeling a bit panicked! Has anyone else experienced this before? How will I know when it's GO time? This is our first baby so I feel I'm being overly analytical....any advice?