Baby dropping and then coming back out?

Yes, that seems to be happening to me. Despite the following feelings that I constantly have - sharp pains very low down, decrease in pressure up high, easier breathing, increase in urination...all of which would indicate he has dropped, I keep getting told he hasn't engaged. My last 4 appointments actually show him disengaging. I started about 36 weeks 3/5 engaged (so the midwife could feel 3/5 of the baby's head above my pelvis) then the next was 4/5 (so 4/5 could be felt above), then 5/5 and free - both of which means they can feel all of the head still and he isn't in my pelvis. So he seems to be going backwards unless all of these people are wrong (4 different midwives / consultants). It is really frustrating although I've heard it doesn't necessarily mean I will be overdue. I don't think it has anything to do with pelvis size, more just the baby moving in and out as it suits them! Kinda like dipping your toes into cold water...'yes I will, no! no! I can't, I'm not ready yet!'.