Constipation and sleep

T
I'm 5 weeks 5 days and since week 4 I have to go to the bathroom for a bowel movement a couple of times during the night. I initially wake up and literally have to sit on the commode for up to 15 mins before something happens and then I'm up about an hour later to do it all again!!  It seems like my body only wants to have a bowel movement at night. I just want to get a good nights rest and not be constipated.  Any suggestions??