I understand what you are going through - I have two strong boughts of pre-labour with my first child. They can get very intense and it really seems like this could be it but then they falter, change or stop! Very frustrating. It is a very good sign that labour is imminent though, and it will really happen soon. They are also probably helping to slowly dilate your cervix through the first 1-2 cms. Hopefully all of this makes active labour much shorter for you! The most helpful thing to get my labour really going was doing the deed, and that might be the last thing you feel like at the moment, but it tends to work!
Good luck