Hi, I am sorry to say that I had pre labour with my son for about 2 weeks. It was exactly the same as yours except mine was at night and I couldn't sleep much for 2 weeks and your post has brought back memories! But when I did finally go into propper labour and went to hospital, I was 8cm dialated and the midwife artificially broke my waters and he was born in an hour, completely naturally (ie no drugs!). So in hindsight although I was in pain for so long I was so proud of myself for doing it all by myself and having a natural birth this time around. For me the pain changed when I went into propper labour to being pains around my lower back and belly like a belt tightening around me and it was more intense.
Good luck Ihope things start really happening soon!
ETA, maybe try some accupuncture or a pg massage?? Hot curries, inserting evening primrose oil and some light walking are said to help as well...