Stomache tightning,whats happening?first baby so dont no?

ok so im 36 + 1 weeks, iv had the runs twice in the night over a 2 weeks,then on the 1st feb i had a bleed so i was admited to hospital,they said they dont no if its a show or not but everything was fine,baby was fine so not to worry.baby was partly engajed.went for a midwife check on the 7th feb,she said baby is fully engajed now.now last night in the super market on the 9th feb my belly kept tightening, i could feel the build up getting tighter,tighter than iv ever felt before.then it would relax then it would come back up, this happend for about 20 minutes. it wasnt painful but did slightly take my breath away and it was so uncomfertable. now this morning i feel so so heavy, any idea ladies,should i pack my hospital bag?