constipation

Okay so I am almost 39 weeks and this last week I have not have an easy time going to the bathroom. I have tried to up my greens and fiber but it just sees like a pain going to the bathroom. I have the urge just doesn't seem like it is not right at my door. Idk if this is constipation but first time I have even really seen it this pregnancy.. does anyone else know what I am talking about?! I thought this is the time I'm supposed to be clearing out because if babies size