Prodromal Labour

Anyone else experincing or experienced prodromal labour. I have been having contractions for the last 6 days. I am now 36+3 they happen usually start in afternoon and get worse at night. Thry are painful.but dont increase with intensity like real ones. I've gone into L&D; twice only to be sent home as there were no changed to cervix.Im shortening and thinning a bit but 0%dilated . Just wondering how long other people dealt with this for. It's very frustrating as its quite painful but not progressing. Dr told me there's no way to know how long it will be could be days or weeks but thinks I probably won't make it to 40wks.