Am i in labour.... any body had this experiance?? 36 +5 weeks?

Hi im 36 +5 weeks pregnant...i have been losing my mucos plug over the last few weeks but none of it has had blood in it. then today i started havin bad period cramps they went away and i then started gettin tightning feeling at the top of my bump that travels down to the bottom of my bump sometimes but mostley stays at the top.. also i have backache that comes and goes. all these pains are coming and going. the pain is bearable but still painfull. I aklso feel like i need a poo but wen i go to the toilet i dont... am in labour or just thinking too far ahead .have any of you exsperianced this and been in labour? feel stupid to ring the hospital. all anwsers will be helpful thanxs xx