38+4 extremely exhausted

has anybody else experienced this i am exhausted beyond belief worse than in the very early days of pregnancy.  Everything is a chore i literally keep bursting into tears, im sleeping on and off all day and night and no amount of sleep is ever enough.  I have been having disturbed nights for months now so im used to that but im that tired im getting headaches etc.  I have never experienced tiredness like it in my life! I thought you were meant to get a burst of energy towards the end. Could this be a sign that labor is imminent? I had a bloody show a week ago, ive had back pain and period cramps but just not in any pattern sometimes my back feels like it is going to snap and the past few days i have felt quite sickly.  I was checked by the midwife a few days ago I am 1/5th engaged basically babys whole head is there but my cervix is unfavourable, any body else similar? x